/**
 * xterm.js: xterm, in the browser
 * Originally forked from (with the author's permission):
 *   Fabrice Bellard's javascript vt100 for jslinux:
 *   http://bellard.org/jslinux/
 *   Copyright (c) 2011 Fabrice Bellard
 *   The original design remains. The terminal itself
 *   has been extended to include xterm CSI codes, among
 *   other features.
 * @license MIT
 */

import { CompositionHelper } from './CompositionHelper.js';
import { EventEmitter } from './EventEmitter.js';
import { Viewport } from './Viewport.js';
import { rightClickHandler, pasteHandler, copyHandler } from './handlers/Clipboard.js';
import { CircularList } from './utils/CircularList.js';
import * as Browser from './utils/Browser';
import * as Keyboard from './utils/Keyboard';

/**
 * Terminal Emulation References:
 *   http://vt100.net/
 *   http://invisible-island.net/xterm/ctlseqs/ctlseqs.txt
 *   http://invisible-island.net/xterm/ctlseqs/ctlseqs.html
 *   http://invisible-island.net/vttest/
 *   http://www.inwap.com/pdp10/ansicode.txt
 *   http://linux.die.net/man/4/console_codes
 *   http://linux.die.net/man/7/urxvt
 */

// Let it work inside Node.js for automated testing purposes.
var document = (typeof window != 'undefined') ? window.document : null;

/**
 * States
 */
var normal = 0, escaped = 1, csi = 2, osc = 3, charset = 4, dcs = 5, ignore = 6;

/**
 * Terminal
 */

/**
 * Creates a new `Terminal` object.
 *
 * @param {object} options An object containing a set of options, the available options are:
 *   - `cursorBlink` (boolean): Whether the terminal cursor blinks
 *   - `cols` (number): The number of columns of the terminal (horizontal size)
 *   - `rows` (number): The number of rows of the terminal (vertical size)
 *
 * @public
 * @class Xterm Xterm
 * @alias module:xterm/src/xterm
 */
function Terminal(options) {
  var self = this;

  if (!(this instanceof Terminal)) {
    return new Terminal(arguments[0], arguments[1], arguments[2]);
  }

  self.browser = Browser;
  self.cancel = Terminal.cancel;

  EventEmitter.call(this);

  if (typeof options === 'number') {
    options = {
      cols: arguments[0],
      rows: arguments[1],
      handler: arguments[2]
    };
  }

  options = options || {};


  Object.keys(Terminal.defaults).forEach(function(key) {
    if (options[key] == null) {
      options[key] = Terminal.options[key];

      if (Terminal[key] !== Terminal.defaults[key]) {
        options[key] = Terminal[key];
      }
    }
    self[key] = options[key];
  });

  if (options.colors.length === 8) {
    options.colors = options.colors.concat(Terminal._colors.slice(8));
  } else if (options.colors.length === 16) {
    options.colors = options.colors.concat(Terminal._colors.slice(16));
  } else if (options.colors.length === 10) {
    options.colors = options.colors.slice(0, -2).concat(
      Terminal._colors.slice(8, -2), options.colors.slice(-2));
  } else if (options.colors.length === 18) {
    options.colors = options.colors.concat(
      Terminal._colors.slice(16, -2), options.colors.slice(-2));
  }
  this.colors = options.colors;

  this.options = options;

  // this.context = options.context || window;
  // this.document = options.document || document;
  this.parent = options.body || options.parent || (
    document ? document.getElementsByTagName('body')[0] : null
  );

  this.cols = options.cols || options.geometry[0];
  this.rows = options.rows || options.geometry[1];
  this.geometry = [this.cols, this.rows];

  if (options.handler) {
    this.on('data', options.handler);
  }

  /**
   * The scroll position of the y cursor, ie. ybase + y = the y position within the entire
   * buffer
   */
  this.ybase = 0;

  /**
   * The scroll position of the viewport
   */
  this.ydisp = 0;

  /**
   * The cursor's x position after ybase
   */
  this.x = 0;

  /**
   * The cursor's y position after ybase
   */
  this.y = 0;

  /**
   * Used to debounce the refresh function
   */
  this.isRefreshing = false;

  /**
   * Whether there is a full terminal refresh queued
   */

  this.cursorState = 0;
  this.cursorHidden = false;
  this.convertEol;
  this.state = 0;
  this.queue = '';
  this.scrollTop = 0;
  this.scrollBottom = this.rows - 1;
  this.customKeydownHandler = null;

  // modes
  this.applicationKeypad = false;
  this.applicationCursor = false;
  this.originMode = false;
  this.insertMode = false;
  this.wraparoundMode = true; // defaults: xterm - true, vt100 - false
  this.normal = null;

  // charset
  this.charset = null;
  this.gcharset = null;
  this.glevel = 0;
  this.charsets = [null];

  // mouse properties
  this.decLocator;
  this.x10Mouse;
  this.vt200Mouse;
  this.vt300Mouse;
  this.normalMouse;
  this.mouseEvents;
  this.sendFocus;
  this.utfMouse;
  this.sgrMouse;
  this.urxvtMouse;

  // misc
  this.element;
  this.children;
  this.refreshStart;
  this.refreshEnd;
  this.savedX;
  this.savedY;
  this.savedCols;

  // stream
  this.readable = true;
  this.writable = true;

  this.defAttr = (0 << 18) | (257 << 9) | (256 << 0);
  this.curAttr = this.defAttr;

  this.params = [];
  this.currentParam = 0;
  this.prefix = '';
  this.postfix = '';

  // leftover surrogate high from previous write invocation
  this.surrogate_high = '';

  /**
   * An array of all lines in the entire buffer, including the prompt. The lines are array of
   * characters which are 2-length arrays where [0] is an attribute and [1] is the character.
   */
  this.lines = new CircularList(this.scrollback);
  var i = this.rows;
  while (i--) {
    this.lines.push(this.blankLine());
  }

  this.tabs;
  this.setupStops();

  // Store if user went browsing history in scrollback
  this.userScrolling = false;
}

inherits(Terminal, EventEmitter);

/**
 * back_color_erase feature for xterm.
 */
Terminal.prototype.eraseAttr = function() {
  // if (this.is('screen')) return this.defAttr;
  return (this.defAttr & ~0x1ff) | (this.curAttr & 0x1ff);
};

/**
 * Colors
 */

// Colors 0-15
Terminal.tangoColors = [
  // dark:
  '#2e3436',
  '#cc0000',
  '#4e9a06',
  '#c4a000',
  '#3465a4',
  '#75507b',
  '#06989a',
  '#d3d7cf',
  // bright:
  '#555753',
  '#ef2929',
  '#8ae234',
  '#fce94f',
  '#729fcf',
  '#ad7fa8',
  '#34e2e2',
  '#eeeeec'
];

// Colors 0-15 + 16-255
// Much thanks to TooTallNate for writing this.
Terminal.colors = (function() {
  var colors = Terminal.tangoColors.slice()
  , r = [0x00, 0x5f, 0x87, 0xaf, 0xd7, 0xff]
  , i;

  // 16-231
  i = 0;
  for (; i < 216; i++) {
    out(r[(i / 36) % 6 | 0], r[(i / 6) % 6 | 0], r[i % 6]);
  }

  // 232-255 (grey)
  i = 0;
  for (; i < 24; i++) {
    r = 8 + i * 10;
    out(r, r, r);
  }

  function out(r, g, b) {
    colors.push('#' + hex(r) + hex(g) + hex(b));
  }

  function hex(c) {
    c = c.toString(16);
    return c.length < 2 ? '0' + c : c;
  }

  return colors;
})();

Terminal._colors = Terminal.colors.slice();

Terminal.vcolors = (function() {
  var out = []
  , colors = Terminal.colors
  , i = 0
  , color;

  for (; i < 256; i++) {
    color = parseInt(colors[i].substring(1), 16);
    out.push([
      (color >> 16) & 0xff,
      (color >> 8) & 0xff,
      color & 0xff
    ]);
  }

  return out;
})();

/**
 * Options
 */

Terminal.defaults = {
  colors: Terminal.colors,
  theme: 'default',
  convertEol: false,
  termName: 'xterm',
  geometry: [80, 24],
  cursorBlink: false,
  visualBell: false,
  popOnBell: false,
  scrollback: 1000,
  screenKeys: false,
  debug: false,
  cancelEvents: false
  // programFeatures: false,
  // focusKeys: false,
};

Terminal.options = {};

Terminal.focus = null;

each(keys(Terminal.defaults), function(key) {
  Terminal[key] = Terminal.defaults[key];
  Terminal.options[key] = Terminal.defaults[key];
});

/**
 * Focus the terminal. Delegates focus handling to the terminal's DOM element.
 */
Terminal.prototype.focus = function() {
  return this.textarea.focus();
};

/**
 * Retrieves an option's value from the terminal.
 * @param {string} key The option key.
 */
Terminal.prototype.getOption = function(key, value) {
  if (!(key in Terminal.defaults)) {
    throw new Error('No option with key "' + key + '"');
  }

  if (typeof this.options[key] !== 'undefined') {
    return this.options[key];
  }

  return this[key];
};

/**
 * Sets an option on the terminal.
 * @param {string} key The option key.
 * @param {string} value The option value.
 */
Terminal.prototype.setOption = function(key, value) {
  if (!(key in Terminal.defaults)) {
    throw new Error('No option with key "' + key + '"');
  }
  this[key] = value;
  this.options[key] = value;
};

/**
 * Binds the desired focus behavior on a given terminal object.
 *
 * @static
 */
Terminal.bindFocus = function (term) {
  on(term.textarea, 'focus', function (ev) {
    if (term.sendFocus) {
      term.send('\x1b[I');
    }
    term.element.classList.add('focus');
    term.showCursor();
    Terminal.focus = term;
    term.emit('focus', {terminal: term});
  });
};

/**
 * Blur the terminal. Delegates blur handling to the terminal's DOM element.
 */
Terminal.prototype.blur = function() {
  return this.textarea.blur();
};

/**
 * Binds the desired blur behavior on a given terminal object.
 *
 * @static
 */
Terminal.bindBlur = function (term) {
  on(term.textarea, 'blur', function (ev) {
    term.refresh(term.y, term.y);
    if (term.sendFocus) {
      term.send('\x1b[O');
    }
    term.element.classList.remove('focus');
    Terminal.focus = null;
    term.emit('blur', {terminal: term});
  });
};

/**
 * Initialize default behavior
 */
Terminal.prototype.initGlobal = function() {
  var term = this;

  Terminal.bindKeys(this);
  Terminal.bindFocus(this);
  Terminal.bindBlur(this);

  // Bind clipboard functionality
  on(this.element, 'copy', function (ev) {
    copyHandler.call(this, ev, term);
  });
  on(this.textarea, 'paste', function (ev) {
    pasteHandler.call(this, ev, term);
  });
  on(this.element, 'paste', function (ev) {
    pasteHandler.call(this, ev, term);
  });

  function rightClickHandlerWrapper (ev) {
    rightClickHandler.call(this, ev, term);
  }

  if (term.browser.isFirefox) {
    on(this.element, 'mousedown', function (ev) {
      if (ev.button == 2) {
        rightClickHandlerWrapper(ev);
      }
    });
  } else {
    on(this.element, 'contextmenu', rightClickHandlerWrapper);
  }
};

/**
 * Apply key handling to the terminal
 */
Terminal.bindKeys = function(term) {
  on(term.element, 'keydown', function(ev) {
    if (document.activeElement != this) {
      return;
    }
    term.keyDown(ev);
  }, true);

  on(term.element, 'keypress', function(ev) {
    if (document.activeElement != this) {
      return;
    }
    term.keyPress(ev);
  }, true);

  on(term.element, 'keyup', term.focus.bind(term));

  on(term.textarea, 'keydown', function(ev) {
    term.keyDown(ev);
  }, true);

  on(term.textarea, 'keypress', function(ev) {
    term.keyPress(ev);
    // Truncate the textarea's value, since it is not needed
    this.value = '';
  }, true);

  on(term.textarea, 'compositionstart', term.compositionHelper.compositionstart.bind(term.compositionHelper));
  on(term.textarea, 'compositionupdate', term.compositionHelper.compositionupdate.bind(term.compositionHelper));
  on(term.textarea, 'compositionend', term.compositionHelper.compositionend.bind(term.compositionHelper));
  term.on('refresh', term.compositionHelper.updateCompositionElements.bind(term.compositionHelper));
};


/**
 * Insert the given row to the terminal or produce a new one
 * if no row argument is passed. Return the inserted row.
 * @param {HTMLElement} row (optional) The row to append to the terminal.
 */
Terminal.prototype.insertRow = function (row) {
  if (typeof row != 'object') {
    row = document.createElement('div');
  }

  this.rowContainer.appendChild(row);
  this.children.push(row);

  return row;
};

/**
 * Opens the terminal within an element.
 *
 * @param {HTMLElement} parent The element to create the terminal within.
 */
Terminal.prototype.open = function(parent) {
  var self=this, i=0, div;

  this.parent = parent || this.parent;

  if (!this.parent) {
    throw new Error('Terminal requires a parent element.');
  }

  // Grab global elements
  this.context = this.parent.ownerDocument.defaultView;
  this.document = this.parent.ownerDocument;
  this.body = this.document.getElementsByTagName('body')[0];

  //Create main element container
  this.element = this.document.createElement('div');
  this.element.classList.add('terminal');
  this.element.classList.add('xterm');
  this.element.classList.add('xterm-theme-' + this.theme);

  this.element.style.height
  this.element.setAttribute('tabindex', 0);

  this.viewportElement = document.createElement('div');
  this.viewportElement.classList.add('xterm-viewport');
  this.element.appendChild(this.viewportElement);
  this.viewportScrollArea = document.createElement('div');
  this.viewportScrollArea.classList.add('xterm-scroll-area');
  this.viewportElement.appendChild(this.viewportScrollArea);

  // Create the container that will hold the lines of the terminal and then
  // produce the lines the lines.
  this.rowContainer = document.createElement('div');
  this.rowContainer.classList.add('xterm-rows');
  this.element.appendChild(this.rowContainer);
  this.children = [];

  // Create the container that will hold helpers like the textarea for
  // capturing DOM Events. Then produce the helpers.
  this.helperContainer = document.createElement('div');
  this.helperContainer.classList.add('xterm-helpers');
  // TODO: This should probably be inserted once it's filled to prevent an additional layout
  this.element.appendChild(this.helperContainer);
  this.textarea = document.createElement('textarea');
  this.textarea.classList.add('xterm-helper-textarea');
  this.textarea.setAttribute('autocorrect', 'off');
  this.textarea.setAttribute('autocapitalize', 'off');
  this.textarea.setAttribute('spellcheck', 'false');
  this.textarea.tabIndex = 0;
  this.textarea.addEventListener('focus', function() {
    self.emit('focus', {terminal: self});
  });
  this.textarea.addEventListener('blur', function() {
    self.emit('blur', {terminal: self});
  });
  this.helperContainer.appendChild(this.textarea);

  this.compositionView = document.createElement('div');
  this.compositionView.classList.add('composition-view');
  this.compositionHelper = new CompositionHelper(this.textarea, this.compositionView, this);
  this.helperContainer.appendChild(this.compositionView);

  this.charMeasureElement = document.createElement('div');
  this.charMeasureElement.classList.add('xterm-char-measure-element');
  this.charMeasureElement.innerHTML = 'W';
  this.helperContainer.appendChild(this.charMeasureElement);

  for (; i < this.rows; i++) {
    this.insertRow();
  }
  this.parent.appendChild(this.element);

  this.viewport = new Viewport(this, this.viewportElement, this.viewportScrollArea, this.charMeasureElement);

  // Draw the screen.
  this.refresh(0, this.rows - 1);

  // Initialize global actions that
  // need to be taken on the document.
  this.initGlobal();

  // Ensure there is a Terminal.focus.
  this.focus();

  on(this.element, 'click', function() {
    var selection = document.getSelection(),
        collapsed = selection.isCollapsed,
        isRange = typeof collapsed == 'boolean' ? !collapsed : selection.type == 'Range';
    if (!isRange) {
      self.focus();
    }
  });

  // Listen for mouse events and translate
  // them into terminal mouse protocols.
  this.bindMouse();

  // Figure out whether boldness affects
  // the character width of monospace fonts.
  if (Terminal.brokenBold == null) {
    Terminal.brokenBold = isBoldBroken(this.document);
  }

  /**
   * This event is emitted when terminal has completed opening.
   *
   * @event open
   */
  this.emit('open');
};


/**
 * Attempts to load an add-on using CommonJS or RequireJS (whichever is available).
 * @param {string} addon The name of the addon to load
 * @static
 */
Terminal.loadAddon = function(addon, callback) {
  if (typeof exports === 'object' && typeof module === 'object') {
    // CommonJS
    return require('./addons/' + addon + '/' + addon);
  } else if (typeof define == 'function') {
    // RequireJS
    return require(['./addons/' + addon + '/' + addon], callback);
  } else {
    console.error('Cannot load a module without a CommonJS or RequireJS environment.');
    return false;
  }
};


/**
 * XTerm mouse events
 * http://invisible-island.net/xterm/ctlseqs/ctlseqs.html#Mouse%20Tracking
 * To better understand these
 * the xterm code is very helpful:
 * Relevant files:
 *   button.c, charproc.c, misc.c
 * Relevant functions in xterm/button.c:
 *   BtnCode, EmitButtonCode, EditorButton, SendMousePosition
 */
Terminal.prototype.bindMouse = function() {
  var el = this.element, self = this, pressed = 32;

  // mouseup, mousedown, wheel
  // left click: ^[[M 3<^[[M#3<
  // wheel up: ^[[M`3>
  function sendButton(ev) {
    var button
    , pos;

    // get the xterm-style button
    button = getButton(ev);

    // get mouse coordinates
    pos = getCoords(ev);
    if (!pos) return;

    sendEvent(button, pos);

    switch (ev.overrideType || ev.type) {
      case 'mousedown':
        pressed = button;
        break;
      case 'mouseup':
        // keep it at the left
        // button, just in case.
        pressed = 32;
        break;
      case 'wheel':
        // nothing. don't
        // interfere with
        // `pressed`.
        break;
    }
  }

  // motion example of a left click:
  // ^[[M 3<^[[M@4<^[[M@5<^[[M@6<^[[M@7<^[[M#7<
  function sendMove(ev) {
    var button = pressed
    , pos;

    pos = getCoords(ev);
    if (!pos) return;

    // buttons marked as motions
    // are incremented by 32
    button += 32;

    sendEvent(button, pos);
  }

  // encode button and
  // position to characters
  function encode(data, ch) {
    if (!self.utfMouse) {
      if (ch === 255) return data.push(0);
      if (ch > 127) ch = 127;
      data.push(ch);
    } else {
      if (ch === 2047) return data.push(0);
      if (ch < 127) {
        data.push(ch);
      } else {
        if (ch > 2047) ch = 2047;
        data.push(0xC0 | (ch >> 6));
        data.push(0x80 | (ch & 0x3F));
      }
    }
  }

  // send a mouse event:
  // regular/utf8: ^[[M Cb Cx Cy
  // urxvt: ^[[ Cb ; Cx ; Cy M
  // sgr: ^[[ Cb ; Cx ; Cy M/m
  // vt300: ^[[ 24(1/3/5)~ [ Cx , Cy ] \r
  // locator: CSI P e ; P b ; P r ; P c ; P p & w
  function sendEvent(button, pos) {
    // self.emit('mouse', {
    //   x: pos.x - 32,
    //   y: pos.x - 32,
    //   button: button
    // });

    if (self.vt300Mouse) {
      // NOTE: Unstable.
      // http://www.vt100.net/docs/vt3xx-gp/chapter15.html
      button &= 3;
      pos.x -= 32;
      pos.y -= 32;
      var data = '\x1b[24';
      if (button === 0) data += '1';
      else if (button === 1) data += '3';
      else if (button === 2) data += '5';
      else if (button === 3) return;
      else data += '0';
      data += '~[' + pos.x + ',' + pos.y + ']\r';
      self.send(data);
      return;
    }

    if (self.decLocator) {
      // NOTE: Unstable.
      button &= 3;
      pos.x -= 32;
      pos.y -= 32;
      if (button === 0) button = 2;
      else if (button === 1) button = 4;
      else if (button === 2) button = 6;
      else if (button === 3) button = 3;
      self.send('\x1b['
                + button
                + ';'
                + (button === 3 ? 4 : 0)
                + ';'
                + pos.y
                + ';'
                + pos.x
                + ';'
                + (pos.page || 0)
                + '&w');
      return;
    }

    if (self.urxvtMouse) {
      pos.x -= 32;
      pos.y -= 32;
      pos.x++;
      pos.y++;
      self.send('\x1b[' + button + ';' + pos.x + ';' + pos.y + 'M');
      return;
    }

    if (self.sgrMouse) {
      pos.x -= 32;
      pos.y -= 32;
      self.send('\x1b[<'
                + (((button & 3) === 3 ? button & ~3 : button) - 32)
                + ';'
                + pos.x
                + ';'
                + pos.y
                + ((button & 3) === 3 ? 'm' : 'M'));
      return;
    }

    var data = [];

    encode(data, button);
    encode(data, pos.x);
    encode(data, pos.y);

    self.send('\x1b[M' + String.fromCharCode.apply(String, data));
  }

  function getButton(ev) {
    var button
    , shift
    , meta
    , ctrl
    , mod;

    // two low bits:
    // 0 = left
    // 1 = middle
    // 2 = right
    // 3 = release
    // wheel up/down:
    // 1, and 2 - with 64 added
    switch (ev.overrideType || ev.type) {
      case 'mousedown':
        button = ev.button != null
          ? +ev.button
        : ev.which != null
          ? ev.which - 1
        : null;

        if (self.browser.isMSIE) {
          button = button === 1 ? 0 : button === 4 ? 1 : button;
        }
        break;
      case 'mouseup':
        button = 3;
        break;
      case 'DOMMouseScroll':
        button = ev.detail < 0
          ? 64
        : 65;
        break;
      case 'wheel':
        button = ev.wheelDeltaY > 0
          ? 64
        : 65;
        break;
    }

    // next three bits are the modifiers:
    // 4 = shift, 8 = meta, 16 = control
    shift = ev.shiftKey ? 4 : 0;
    meta = ev.metaKey ? 8 : 0;
    ctrl = ev.ctrlKey ? 16 : 0;
    mod = shift | meta | ctrl;

    // no mods
    if (self.vt200Mouse) {
      // ctrl only
      mod &= ctrl;
    } else if (!self.normalMouse) {
      mod = 0;
    }

    // increment to SP
    button = (32 + (mod << 2)) + button;

    return button;
  }

  // mouse coordinates measured in cols/rows
  function getCoords(ev) {
    var x, y, w, h, el;

    // ignore browsers without pageX for now
    if (ev.pageX == null) return;

    x = ev.pageX;
    y = ev.pageY;
    el = self.element;

    // should probably check offsetParent
    // but this is more portable
    while (el && el !== self.document.documentElement) {
      x -= el.offsetLeft;
      y -= el.offsetTop;
      el = 'offsetParent' in el
        ? el.offsetParent
      : el.parentNode;
    }

    // convert to cols/rows
    w = self.element.clientWidth;
    h = self.element.clientHeight;
    x = Math.ceil((x / w) * self.cols);
    y = Math.ceil((y / h) * self.rows);

    // be sure to avoid sending
    // bad positions to the program
    if (x < 0) x = 0;
    if (x > self.cols) x = self.cols;
    if (y < 0) y = 0;
    if (y > self.rows) y = self.rows;

    // xterm sends raw bytes and
    // starts at 32 (SP) for each.
    x += 32;
    y += 32;

    return {
      x: x,
      y: y,
      type: 'wheel'
    };
  }

  on(el, 'mousedown', function(ev) {
    if (!self.mouseEvents) return;

    // send the button
    sendButton(ev);

    // ensure focus
    self.focus();

    // fix for odd bug
    //if (self.vt200Mouse && !self.normalMouse) {
    if (self.vt200Mouse) {
      ev.overrideType = 'mouseup';
      sendButton(ev);
      return self.cancel(ev);
    }

    // bind events
    if (self.normalMouse) on(self.document, 'mousemove', sendMove);

    // x10 compatibility mode can't send button releases
    if (!self.x10Mouse) {
      on(self.document, 'mouseup', function up(ev) {
        sendButton(ev);
        if (self.normalMouse) off(self.document, 'mousemove', sendMove);
        off(self.document, 'mouseup', up);
        return self.cancel(ev);
      });
    }

    return self.cancel(ev);
  });

  //if (self.normalMouse) {
  //  on(self.document, 'mousemove', sendMove);
  //}

  on(el, 'wheel', function(ev) {
    if (!self.mouseEvents) return;
    if (self.x10Mouse
        || self.vt300Mouse
        || self.decLocator) return;
    sendButton(ev);
    return self.cancel(ev);
  });

  // allow wheel scrolling in
  // the shell for example
  on(el, 'wheel', function(ev) {
    if (self.mouseEvents) return;
    self.viewport.onWheel(ev);
    return self.cancel(ev);
  });
};

/**
 * Destroys the terminal.
 */
Terminal.prototype.destroy = function() {
  this.readable = false;
  this.writable = false;
  this._events = {};
  this.handler = function() {};
  this.write = function() {};
  if (this.element.parentNode) {
    this.element.parentNode.removeChild(this.element);
  }
  //this.emit('close');
};


/**
 * Flags used to render terminal text properly
 */
Terminal.flags = {
  BOLD: 1,
  UNDERLINE: 2,
  BLINK: 4,
  INVERSE: 8,
  INVISIBLE: 16
}

/**
 * Refreshes (re-renders) terminal content within two rows (inclusive)
 *
 * Rendering Engine:
 *
 * In the screen buffer, each character is stored as a an array with a character
 * and a 32-bit integer:
 *   - First value: a utf-16 character.
 *   - Second value:
 *   - Next 9 bits: background color (0-511).
 *   - Next 9 bits: foreground color (0-511).
 *   - Next 14 bits: a mask for misc. flags:
 *     - 1=bold
 *     - 2=underline
 *     - 4=blink
 *     - 8=inverse
 *     - 16=invisible
 *
 * @param {number} start The row to start from (between 0 and terminal's height terminal - 1)
 * @param {number} end The row to end at (between fromRow and terminal's height terminal - 1)
 * @param {boolean} queue Whether the refresh should ran right now or be queued
 */
Terminal.prototype.refresh = function(start, end, queue) {
  var self = this;

  // queue defaults to true
  queue = (typeof queue == 'undefined') ? true : queue;

  /**
   * The refresh queue allows refresh to execute only approximately 30 times a second. For
   * commands that pass a significant amount of output to the write function, this prevents the
   * terminal from maxing out the CPU and making the UI unresponsive. While commands can still
   * run beyond what they do on the terminal, it is far better with a debounce in place as
   * every single terminal manipulation does not need to be constructed in the DOM.
   *
   * A side-effect of this is that it makes ^C to interrupt a process seem more responsive.
   */
  if (queue) {
    // If refresh should be queued, order the refresh and return.
    if (this._refreshIsQueued) {
      // If a refresh has already been queued, just order a full refresh next
      this._fullRefreshNext = true;
    } else {
      setTimeout(function () {
        self.refresh(start, end, false);
      }, 34)
      this._refreshIsQueued = true;
    }
    return;
  }

  // If refresh should be run right now (not be queued), release the lock
  this._refreshIsQueued = false;

  // If multiple refreshes were requested, make a full refresh.
  if (this._fullRefreshNext) {
    start = 0;
    end = this.rows - 1;
    this._fullRefreshNext = false // reset lock
  }

  var x, y, i, line, out, ch, ch_width, width, data, attr, bg, fg, flags, row, parent, focused = document.activeElement;

  // If this is a big refresh, remove the terminal rows from the DOM for faster calculations
  if (end - start >= this.rows / 2) {
    parent = this.element.parentNode;
    if (parent) {
      this.element.removeChild(this.rowContainer);
    }
  }

  width = this.cols;
  y = start;

  if (end >= this.rows.length) {
    this.log('`end` is too large. Most likely a bad CSR.');
    end = this.rows.length - 1;
  }

  for (; y <= end; y++) {
    row = y + this.ydisp;

    line = this.lines.get(row);
    out = '';

    if (this.y === y - (this.ybase - this.ydisp)
        && this.cursorState
        && !this.cursorHidden) {
      x = this.x;
    } else {
      x = -1;
    }

    attr = this.defAttr;
    i = 0;

    for (; i < width; i++) {
      data = line[i][0];
      ch = line[i][1];
      ch_width = line[i][2];
      if (!ch_width)
        continue;

      if (i === x) data = -1;

      if (data !== attr) {
        if (attr !== this.defAttr) {
          out += '</span>';
        }
        if (data !== this.defAttr) {
          if (data === -1) {
            out += '<span class="reverse-video terminal-cursor';
            if (this.cursorBlink) {
              out += ' blinking';
            }
            out += '">';
          } else {
            var classNames = [];

            bg = data & 0x1ff;
            fg = (data >> 9) & 0x1ff;
            flags = data >> 18;

            if (flags & Terminal.flags.BOLD) {
              if (!Terminal.brokenBold) {
                classNames.push('xterm-bold');
              }
              // See: XTerm*boldColors
              if (fg < 8) fg += 8;
            }

            if (flags & Terminal.flags.UNDERLINE) {
              classNames.push('xterm-underline');
            }

            if (flags & Terminal.flags.BLINK) {
              classNames.push('xterm-blink');
            }

            // If inverse flag is on, then swap the foreground and background variables.
            if (flags & Terminal.flags.INVERSE) {
              /* One-line variable swap in JavaScript: http://stackoverflow.com/a/16201730 */
              bg = [fg, fg = bg][0];
              // Should inverse just be before the
              // above boldColors effect instead?
              if ((flags & 1) && fg < 8) fg += 8;
            }

            if (flags & Terminal.flags.INVISIBLE) {
              classNames.push('xterm-hidden');
            }

            /**
             * Weird situation: Invert flag used black foreground and white background results
             * in invalid background color, positioned at the 256 index of the 256 terminal
             * color map. Pin the colors manually in such a case.
             *
             * Source: https://github.com/sourcelair/xterm.js/issues/57
             */
            if (flags & Terminal.flags.INVERSE) {
              if (bg == 257) {
                bg = 15;
              }
              if (fg == 256) {
                fg = 0;
              }
            }

            if (bg < 256) {
              classNames.push('xterm-bg-color-' + bg);
            }

            if (fg < 256) {
              classNames.push('xterm-color-' + fg);
            }

            out += '<span';
            if (classNames.length) {
              out += ' class="' + classNames.join(' ') + '"';
            }
            out += '>';
          }
        }
      }

      switch (ch) {
        case '&':
          out += '&amp;';
          break;
        case '<':
          out += '&lt;';
          break;
        case '>':
          out += '&gt;';
          break;
        default:
          if (ch <= ' ') {
            out += '&nbsp;';
          } else {
            out += ch;
          }
          break;
      }

      attr = data;
    }

    if (attr !== this.defAttr) {
      out += '</span>';
    }

    this.children[y].innerHTML = out;
  }

  if (parent) {
    this.element.appendChild(this.rowContainer);
  }

  this.emit('refresh', {element: this.element, start: start, end: end});
};

/**
 * Display the cursor element
 */
Terminal.prototype.showCursor = function() {
  if (!this.cursorState) {
    this.cursorState = 1;
    this.refresh(this.y, this.y);
  }
};

/**
 * Scroll the terminal down 1 row, creating a blank line.
 */
Terminal.prototype.scroll = function() {
  var row;

  this.ybase++;

  // TODO: Why is this done twice?
  if (!this.userScrolling) {
    this.ydisp = this.ybase;
  }

  // last line
  row = this.ybase + this.rows - 1;

  // subtract the bottom scroll region
  row -= this.rows - 1 - this.scrollBottom;

  if (row === this.lines.length) {
    // Compensate ybase and ydisp if lines has hit the maximum buffer size
    if (this.lines.length === this.lines.maxLength) {
      this.ybase--;
      if (this.ydisp !== 0) {
        this.ydisp--;
      }
    }
    // Optimization: pushing is faster than splicing when they amount to the same behavior
    this.lines.push(this.blankLine());
  } else {
    // add our new line
    this.lines.splice(row, 0, this.blankLine());
  }

  if (this.scrollTop !== 0) {
    if (this.ybase !== 0) {
      this.ybase--;
      if (!this.userScrolling) {
        this.ydisp = this.ybase;
      }
    }
    this.lines.splice(this.ybase + this.scrollTop, 1);
  }

  // this.maxRange();
  this.updateRange(this.scrollTop);
  this.updateRange(this.scrollBottom);

  /**
   * This event is emitted whenever the terminal is scrolled.
   * The one parameter passed is the new y display position.
   *
   * @event scroll
   */
  this.emit('scroll', this.ydisp);
};

/**
 * Scroll the display of the terminal
 * @param {number} disp The number of lines to scroll down (negatives scroll up).
 * @param {boolean} suppressScrollEvent Don't emit the scroll event as scrollDisp. This is used
 * to avoid unwanted events being handled by the veiwport when the event was triggered from the
 * viewport originally.
 */
Terminal.prototype.scrollDisp = function(disp, suppressScrollEvent) {
  if (disp < 0) {
    this.userScrolling = true;
  } else if (disp + this.ydisp >= this.ybase) {
    this.userScrolling = false;
  }

  this.ydisp += disp;

  if (this.ydisp > this.ybase) {
    this.ydisp = this.ybase;
  } else if (this.ydisp < 0) {
    this.ydisp = 0;
  }

  if (!suppressScrollEvent) {
    this.emit('scroll', this.ydisp);
  }

  this.refresh(0, this.rows - 1);
};

/**
 * Scroll the display of the terminal by a number of pages.
 * @param {number} pageCount The number of pages to scroll (negative scrolls up).
 */
Terminal.prototype.scrollPages = function(pageCount) {
  this.scrollDisp(pageCount * (this.rows - 1));
}

/**
 * Scrolls the display of the terminal to the top.
 */
Terminal.prototype.scrollToTop = function() {
  this.scrollDisp(-this.ydisp);
}

/**
 * Scrolls the display of the terminal to the bottom.
 */
Terminal.prototype.scrollToBottom = function() {
  this.scrollDisp(this.ybase - this.ydisp);
}

/**
 * Writes text to the terminal.
 * @param {string} text The text to write to the terminal.
 */
Terminal.prototype.write = function(data) {
  var l = data.length, i = 0, j, cs, ch, code, low, ch_width, row;

  this.refreshStart = this.y;
  this.refreshEnd = this.y;

  // apply leftover surrogate high from last write
  if (this.surrogate_high) {
    data = this.surrogate_high + data;
    this.surrogate_high = '';
  }

  for (; i < l; i++) {
    ch = data[i];

    // FIXME: higher chars than 0xa0 are not allowed in escape sequences
    //        --> maybe move to default
    code = data.charCodeAt(i);
    if (0xD800 <= code && code <= 0xDBFF) {
      // we got a surrogate high
      // get surrogate low (next 2 bytes)
      low = data.charCodeAt(i+1);
      if (isNaN(low)) {
        // end of data stream, save surrogate high
        this.surrogate_high = ch;
        continue;
      }
      code = ((code - 0xD800) * 0x400) + (low - 0xDC00) + 0x10000;
      ch += data.charAt(i+1);
    }
    // surrogate low - already handled above
    if (0xDC00 <= code && code <= 0xDFFF)
      continue;
    switch (this.state) {
      case normal:
        switch (ch) {
          case '\x07':
            this.bell();
            break;

          // '\n', '\v', '\f'
          case '\n':
          case '\x0b':
          case '\x0c':
            if (this.convertEol) {
              this.x = 0;
            }
            this.y++;
            if (this.y > this.scrollBottom) {
              this.y--;
              this.scroll();
            }
            break;

          // '\r'
          case '\r':
            this.x = 0;
            break;

          // '\b'
          case '\x08':
            if (this.x > 0) {
              this.x--;
            }
            break;

          // '\t'
          case '\t':
            this.x = this.nextStop();
            break;

          // shift out
          case '\x0e':
            this.setgLevel(1);
            break;

          // shift in
          case '\x0f':
            this.setgLevel(0);
            break;

          // '\e'
          case '\x1b':
            this.state = escaped;
            break;

          default:
            // ' '
            // calculate print space
            // expensive call, therefore we save width in line buffer
            ch_width = wcwidth(code);

            if (ch >= ' ') {
              if (this.charset && this.charset[ch]) {
                ch = this.charset[ch];
              }

              row = this.y + this.ybase;

              // insert combining char in last cell
              // FIXME: needs handling after cursor jumps
              if (!ch_width && this.x) {
                // dont overflow left
                if (this.lines.get(row)[this.x-1]) {
                  if (!this.lines.get(row)[this.x-1][2]) {

                    // found empty cell after fullwidth, need to go 2 cells back
                    if (this.lines.get(row)[this.x-2])
                      this.lines.get(row)[this.x-2][1] += ch;

                  } else {
                    this.lines.get(row)[this.x-1][1] += ch;
                  }
                  this.updateRange(this.y);
                }
                break;
              }

              // goto next line if ch would overflow
              // TODO: needs a global min terminal width of 2
              if (this.x+ch_width-1 >= this.cols) {
                // autowrap - DECAWM
                if (this.wraparoundMode) {
                  this.x = 0;
                  this.y++;
                  if (this.y > this.scrollBottom) {
                    this.y--;
                    this.scroll();
                  }
                } else {
                  this.x = this.cols-1;
                  if(ch_width===2)  // FIXME: check for xterm behavior
                    continue;
                }
              }
              row = this.y + this.ybase;

              // insert mode: move characters to right
              if (this.insertMode) {
                // do this twice for a fullwidth char
                for (var moves=0; moves<ch_width; ++moves) {
                  // remove last cell, if it's width is 0
                  // we have to adjust the second last cell as well
                  var removed = this.lines.get(this.y + this.ybase).pop();
                  if (removed[2]===0
                      && this.lines.get(row)[this.cols-2]
                  && this.lines.get(row)[this.cols-2][2]===2)
                    this.lines.get(row)[this.cols-2] = [this.curAttr, ' ', 1];

                  // insert empty cell at cursor
                  this.lines.get(row).splice(this.x, 0, [this.curAttr, ' ', 1]);
                }
              }

              this.lines.get(row)[this.x] = [this.curAttr, ch, ch_width];
              this.x++;
              this.updateRange(this.y);

              // fullwidth char - set next cell width to zero and advance cursor
              if (ch_width===2) {
                this.lines.get(row)[this.x] = [this.curAttr, '', 0];
                this.x++;
              }
            }
            break;
        }
        break;
      case escaped:
        switch (ch) {
          // ESC [ Control Sequence Introducer ( CSI is 0x9b).
          case '[':
            this.params = [];
            this.currentParam = 0;
            this.state = csi;
            break;

          // ESC ] Operating System Command ( OSC is 0x9d).
          case ']':
            this.params = [];
            this.currentParam = 0;
            this.state = osc;
            break;

          // ESC P Device Control String ( DCS is 0x90).
          case 'P':
            this.params = [];
            this.currentParam = 0;
            this.state = dcs;
            break;

          // ESC _ Application Program Command ( APC is 0x9f).
          case '_':
            this.state = ignore;
            break;

          // ESC ^ Privacy Message ( PM is 0x9e).
          case '^':
            this.state = ignore;
            break;

          // ESC c Full Reset (RIS).
          case 'c':
            this.reset();
            break;

          // ESC E Next Line ( NEL is 0x85).
          // ESC D Index ( IND is 0x84).
          case 'E':
            this.x = 0;
            ;
          case 'D':
            this.index();
            break;

          // ESC M Reverse Index ( RI is 0x8d).
          case 'M':
            this.reverseIndex();
            break;

          // ESC % Select default/utf-8 character set.
          // @ = default, G = utf-8
          case '%':
            //this.charset = null;
            this.setgLevel(0);
            this.setgCharset(0, Terminal.charsets.US);
            this.state = normal;
            i++;
            break;

          // ESC (,),*,+,-,. Designate G0-G2 Character Set.
          case '(': // <-- this seems to get all the attention
          case ')':
          case '*':
          case '+':
          case '-':
          case '.':
            switch (ch) {
              case '(':
                this.gcharset = 0;
                break;
              case ')':
                this.gcharset = 1;
                break;
              case '*':
                this.gcharset = 2;
                break;
              case '+':
                this.gcharset = 3;
                break;
              case '-':
                this.gcharset = 1;
                break;
              case '.':
                this.gcharset = 2;
                break;
            }
            this.state = charset;
            break;

          // Designate G3 Character Set (VT300).
          // A = ISO Latin-1 Supplemental.
          // Not implemented.
          case '/':
            this.gcharset = 3;
            this.state = charset;
            i--;
            break;

          // ESC N
          // Single Shift Select of G2 Character Set
          // ( SS2 is 0x8e). This affects next character only.
          case 'N':
            break;
          // ESC O
          // Single Shift Select of G3 Character Set
          // ( SS3 is 0x8f). This affects next character only.
          case 'O':
            break;
          // ESC n
          // Invoke the G2 Character Set as GL (LS2).
          case 'n':
            this.setgLevel(2);
            break;
          // ESC o
          // Invoke the G3 Character Set as GL (LS3).
          case 'o':
            this.setgLevel(3);
            break;
          // ESC |
          // Invoke the G3 Character Set as GR (LS3R).
          case '|':
            this.setgLevel(3);
            break;
          // ESC }
          // Invoke the G2 Character Set as GR (LS2R).
          case '}':
            this.setgLevel(2);
            break;
          // ESC ~
          // Invoke the G1 Character Set as GR (LS1R).
          case '~':
            this.setgLevel(1);
            break;

          // ESC 7 Save Cursor (DECSC).
          case '7':
            this.saveCursor();
            this.state = normal;
            break;

          // ESC 8 Restore Cursor (DECRC).
          case '8':
            this.restoreCursor();
            this.state = normal;
            break;

          // ESC # 3 DEC line height/width
          case '#':
            this.state = normal;
            i++;
            break;

          // ESC H Tab Set (HTS is 0x88).
          case 'H':
            this.tabSet();
            break;

          // ESC = Application Keypad (DECKPAM).
          case '=':
            this.log('Serial port requested application keypad.');
            this.applicationKeypad = true;
            this.viewport.syncScrollArea();
            this.state = normal;
            break;

          // ESC > Normal Keypad (DECKPNM).
          case '>':
            this.log('Switching back to normal keypad.');
            this.applicationKeypad = false;
            this.viewport.syncScrollArea();
            this.state = normal;
            break;

          default:
            this.state = normal;
            this.error('Unknown ESC control: %s.', ch);
            break;
        }
        break;

      case charset:
        switch (ch) {
          case '0': // DEC Special Character and Line Drawing Set.
            cs = Terminal.charsets.SCLD;
            break;
          case 'A': // UK
            cs = Terminal.charsets.UK;
            break;
          case 'B': // United States (USASCII).
            cs = Terminal.charsets.US;
            break;
          case '4': // Dutch
            cs = Terminal.charsets.Dutch;
            break;
          case 'C': // Finnish
          case '5':
            cs = Terminal.charsets.Finnish;
            break;
          case 'R': // French
            cs = Terminal.charsets.French;
            break;
          case 'Q': // FrenchCanadian
            cs = Terminal.charsets.FrenchCanadian;
            break;
          case 'K': // German
            cs = Terminal.charsets.German;
            break;
          case 'Y': // Italian
            cs = Terminal.charsets.Italian;
            break;
          case 'E': // NorwegianDanish
          case '6':
            cs = Terminal.charsets.NorwegianDanish;
            break;
          case 'Z': // Spanish
            cs = Terminal.charsets.Spanish;
            break;
          case 'H': // Swedish
          case '7':
            cs = Terminal.charsets.Swedish;
            break;
          case '=': // Swiss
            cs = Terminal.charsets.Swiss;
            break;
          case '/': // ISOLatin (actually /A)
            cs = Terminal.charsets.ISOLatin;
            i++;
            break;
          default: // Default
            cs = Terminal.charsets.US;
            break;
        }
        this.setgCharset(this.gcharset, cs);
        this.gcharset = null;
        this.state = normal;
        break;

      case osc:
        // OSC Ps ; Pt ST
        // OSC Ps ; Pt BEL
        //   Set Text Parameters.
        if (ch === '\x1b' || ch === '\x07') {
          if (ch === '\x1b') i++;

          this.params.push(this.currentParam);

          switch (this.params[0]) {
            case 0:
            case 1:
            case 2:
              if (this.params[1]) {
                this.title = this.params[1];
                this.handleTitle(this.title);
              }
              break;
            case 3:
              // set X property
              break;
            case 4:
            case 5:
              // change dynamic colors
              break;
            case 10:
            case 11:
            case 12:
            case 13:
            case 14:
            case 15:
            case 16:
            case 17:
            case 18:
            case 19:
              // change dynamic ui colors
              break;
            case 46:
              // change log file
              break;
            case 50:
              // dynamic font
              break;
            case 51:
              // emacs shell
              break;
            case 52:
              // manipulate selection data
              break;
            case 104:
            case 105:
            case 110:
            case 111:
            case 112:
            case 113:
            case 114:
            case 115:
            case 116:
            case 117:
            case 118:
              // reset colors
              break;
          }

          this.params = [];
          this.currentParam = 0;
          this.state = normal;
        } else {
          if (!this.params.length) {
            if (ch >= '0' && ch <= '9') {
              this.currentParam =
                this.currentParam * 10 + ch.charCodeAt(0) - 48;
            } else if (ch === ';') {
              this.params.push(this.currentParam);
              this.currentParam = '';
            }
          } else {
            this.currentParam += ch;
          }
        }
        break;

      case csi:
        // '?', '>', '!'
        if (ch === '?' || ch === '>' || ch === '!') {
          this.prefix = ch;
          break;
        }

        // 0 - 9
        if (ch >= '0' && ch <= '9') {
          this.currentParam = this.currentParam * 10 + ch.charCodeAt(0) - 48;
          break;
        }

        // '$', '"', ' ', '\''
        if (ch === '$' || ch === '"' || ch === ' ' || ch === '\'') {
          this.postfix = ch;
          break;
        }

        this.params.push(this.currentParam);
        this.currentParam = 0;

        // ';'
        if (ch === ';') break;

        this.state = normal;

        switch (ch) {
          // CSI Ps A
          // Cursor Up Ps Times (default = 1) (CUU).
          case 'A':
            this.cursorUp(this.params);
            break;

          // CSI Ps B
          // Cursor Down Ps Times (default = 1) (CUD).
          case 'B':
            this.cursorDown(this.params);
            break;

          // CSI Ps C
          // Cursor Forward Ps Times (default = 1) (CUF).
          case 'C':
            this.cursorForward(this.params);
            break;

          // CSI Ps D
          // Cursor Backward Ps Times (default = 1) (CUB).
          case 'D':
            this.cursorBackward(this.params);
            break;

          // CSI Ps ; Ps H
          // Cursor Position [row;column] (default = [1,1]) (CUP).
          case 'H':
            this.cursorPos(this.params);
            break;

          // CSI Ps J  Erase in Display (ED).
          case 'J':
            this.eraseInDisplay(this.params);
            break;

          // CSI Ps K  Erase in Line (EL).
          case 'K':
            this.eraseInLine(this.params);
            break;

          // CSI Pm m  Character Attributes (SGR).
          case 'm':
            if (!this.prefix) {
              this.charAttributes(this.params);
            }
            break;

          // CSI Ps n  Device Status Report (DSR).
          case 'n':
            if (!this.prefix) {
              this.deviceStatus(this.params);
            }
            break;

            /**
             * Additions
             */

          // CSI Ps @
          // Insert Ps (Blank) Character(s) (default = 1) (ICH).
          case '@':
            this.insertChars(this.params);
            break;

          // CSI Ps E
          // Cursor Next Line Ps Times (default = 1) (CNL).
          case 'E':
            this.cursorNextLine(this.params);
            break;

          // CSI Ps F
          // Cursor Preceding Line Ps Times (default = 1) (CNL).
          case 'F':
            this.cursorPrecedingLine(this.params);
            break;

          // CSI Ps G
          // Cursor Character Absolute  [column] (default = [row,1]) (CHA).
          case 'G':
            this.cursorCharAbsolute(this.params);
            break;

          // CSI Ps L
          // Insert Ps Line(s) (default = 1) (IL).
          case 'L':
            this.insertLines(this.params);
            break;

          // CSI Ps M
          // Delete Ps Line(s) (default = 1) (DL).
          case 'M':
            this.deleteLines(this.params);
            break;

          // CSI Ps P
          // Delete Ps Character(s) (default = 1) (DCH).
          case 'P':
            this.deleteChars(this.params);
            break;

          // CSI Ps X
          // Erase Ps Character(s) (default = 1) (ECH).
          case 'X':
            this.eraseChars(this.params);
            break;

          // CSI Pm `  Character Position Absolute
          //   [column] (default = [row,1]) (HPA).
          case '`':
            this.charPosAbsolute(this.params);
            break;

          // 141 61 a * HPR -
          // Horizontal Position Relative
          case 'a':
            this.HPositionRelative(this.params);
            break;

          // CSI P s c
          // Send Device Attributes (Primary DA).
          // CSI > P s c
          // Send Device Attributes (Secondary DA)
          case 'c':
            this.sendDeviceAttributes(this.params);
            break;

          // CSI Pm d
          // Line Position Absolute  [row] (default = [1,column]) (VPA).
          case 'd':
            this.linePosAbsolute(this.params);
            break;

          // 145 65 e * VPR - Vertical Position Relative
          case 'e':
            this.VPositionRelative(this.params);
            break;

          // CSI Ps ; Ps f
          //   Horizontal and Vertical Position [row;column] (default =
          //   [1,1]) (HVP).
          case 'f':
            this.HVPosition(this.params);
            break;

          // CSI Pm h  Set Mode (SM).
          // CSI ? Pm h - mouse escape codes, cursor escape codes
          case 'h':
            this.setMode(this.params);
            break;

          // CSI Pm l  Reset Mode (RM).
          // CSI ? Pm l
          case 'l':
            this.resetMode(this.params);
            break;

          // CSI Ps ; Ps r
          //   Set Scrolling Region [top;bottom] (default = full size of win-
          //   dow) (DECSTBM).
          // CSI ? Pm r
          case 'r':
            this.setScrollRegion(this.params);
            break;

          // CSI s
          //   Save cursor (ANSI.SYS).
          case 's':
            this.saveCursor(this.params);
            break;

          // CSI u
          //   Restore cursor (ANSI.SYS).
          case 'u':
            this.restoreCursor(this.params);
            break;

            /**
             * Lesser Used
             */

          // CSI Ps I
          // Cursor Forward Tabulation Ps tab stops (default = 1) (CHT).
          case 'I':
            this.cursorForwardTab(this.params);
            break;

          // CSI Ps S  Scroll up Ps lines (default = 1) (SU).
          case 'S':
            this.scrollUp(this.params);
            break;

          // CSI Ps T  Scroll down Ps lines (default = 1) (SD).
          // CSI Ps ; Ps ; Ps ; Ps ; Ps T
          // CSI > Ps; Ps T
          case 'T':
            // if (this.prefix === '>') {
            //   this.resetTitleModes(this.params);
            //   break;
            // }
            // if (this.params.length > 2) {
            //   this.initMouseTracking(this.params);
            //   break;
            // }
            if (this.params.length < 2 && !this.prefix) {
              this.scrollDown(this.params);
            }
            break;

          // CSI Ps Z
          // Cursor Backward Tabulation Ps tab stops (default = 1) (CBT).
          case 'Z':
            this.cursorBackwardTab(this.params);
            break;

          // CSI Ps b  Repeat the preceding graphic character Ps times (REP).
          case 'b':
            this.repeatPrecedingCharacter(this.params);
            break;

          // CSI Ps g  Tab Clear (TBC).
          case 'g':
            this.tabClear(this.params);
            break;

            // CSI Pm i  Media Copy (MC).
            // CSI ? Pm i
            // case 'i':
            //   this.mediaCopy(this.params);
            //   break;

            // CSI Pm m  Character Attributes (SGR).
            // CSI > Ps; Ps m
            // case 'm': // duplicate
            //   if (this.prefix === '>') {
            //     this.setResources(this.params);
            //   } else {
            //     this.charAttributes(this.params);
            //   }
            //   break;

            // CSI Ps n  Device Status Report (DSR).
            // CSI > Ps n
            // case 'n': // duplicate
            //   if (this.prefix === '>') {
            //     this.disableModifiers(this.params);
            //   } else {
            //     this.deviceStatus(this.params);
            //   }
            //   break;

            // CSI > Ps p  Set pointer mode.
            // CSI ! p   Soft terminal reset (DECSTR).
            // CSI Ps$ p
            //   Request ANSI mode (DECRQM).
            // CSI ? Ps$ p
            //   Request DEC private mode (DECRQM).
            // CSI Ps ; Ps " p
          case 'p':
            switch (this.prefix) {
                // case '>':
                //   this.setPointerMode(this.params);
                //   break;
              case '!':
                this.softReset(this.params);
                break;
                // case '?':
                //   if (this.postfix === '$') {
                //     this.requestPrivateMode(this.params);
                //   }
                //   break;
                // default:
                //   if (this.postfix === '"') {
                //     this.setConformanceLevel(this.params);
                //   } else if (this.postfix === '$') {
                //     this.requestAnsiMode(this.params);
                //   }
                //   break;
            }
            break;

            // CSI Ps q  Load LEDs (DECLL).
            // CSI Ps SP q
            // CSI Ps " q
            // case 'q':
            //   if (this.postfix === ' ') {
            //     this.setCursorStyle(this.params);
            //     break;
            //   }
            //   if (this.postfix === '"') {
            //     this.setCharProtectionAttr(this.params);
            //     break;
            //   }
            //   this.loadLEDs(this.params);
            //   break;

            // CSI Ps ; Ps r
            //   Set Scrolling Region [top;bottom] (default = full size of win-
            //   dow) (DECSTBM).
            // CSI ? Pm r
            // CSI Pt; Pl; Pb; Pr; Ps$ r
            // case 'r': // duplicate
            //   if (this.prefix === '?') {
            //     this.restorePrivateValues(this.params);
            //   } else if (this.postfix === '$') {
            //     this.setAttrInRectangle(this.params);
            //   } else {
            //     this.setScrollRegion(this.params);
            //   }
            //   break;

            // CSI s     Save cursor (ANSI.SYS).
            // CSI ? Pm s
            // case 's': // duplicate
            //   if (this.prefix === '?') {
            //     this.savePrivateValues(this.params);
            //   } else {
            //     this.saveCursor(this.params);
            //   }
            //   break;

            // CSI Ps ; Ps ; Ps t
            // CSI Pt; Pl; Pb; Pr; Ps$ t
            // CSI > Ps; Ps t
            // CSI Ps SP t
            // case 't':
            //   if (this.postfix === '$') {
            //     this.reverseAttrInRectangle(this.params);
            //   } else if (this.postfix === ' ') {
            //     this.setWarningBellVolume(this.params);
            //   } else {
            //     if (this.prefix === '>') {
            //       this.setTitleModeFeature(this.params);
            //     } else {
            //       this.manipulateWindow(this.params);
            //     }
            //   }
            //   break;

            // CSI u     Restore cursor (ANSI.SYS).
            // CSI Ps SP u
            // case 'u': // duplicate
            //   if (this.postfix === ' ') {
            //     this.setMarginBellVolume(this.params);
            //   } else {
            //     this.restoreCursor(this.params);
            //   }
            //   break;

            // CSI Pt; Pl; Pb; Pr; Pp; Pt; Pl; Pp$ v
            // case 'v':
            //   if (this.postfix === '$') {
            //     this.copyRectagle(this.params);
            //   }
            //   break;

            // CSI Pt ; Pl ; Pb ; Pr ' w
            // case 'w':
            //   if (this.postfix === '\'') {
            //     this.enableFilterRectangle(this.params);
            //   }
            //   break;

            // CSI Ps x  Request Terminal Parameters (DECREQTPARM).
            // CSI Ps x  Select Attribute Change Extent (DECSACE).
            // CSI Pc; Pt; Pl; Pb; Pr$ x
            // case 'x':
            //   if (this.postfix === '$') {
            //     this.fillRectangle(this.params);
            //   } else {
            //     this.requestParameters(this.params);
            //     //this.__(this.params);
            //   }
            //   break;

            // CSI Ps ; Pu ' z
            // CSI Pt; Pl; Pb; Pr$ z
            // case 'z':
            //   if (this.postfix === '\'') {
            //     this.enableLocatorReporting(this.params);
            //   } else if (this.postfix === '$') {
            //     this.eraseRectangle(this.params);
            //   }
            //   break;

            // CSI Pm ' {
            // CSI Pt; Pl; Pb; Pr$ {
            // case '{':
            //   if (this.postfix === '\'') {
            //     this.setLocatorEvents(this.params);
            //   } else if (this.postfix === '$') {
            //     this.selectiveEraseRectangle(this.params);
            //   }
            //   break;

            // CSI Ps ' |
            // case '|':
            //   if (this.postfix === '\'') {
            //     this.requestLocatorPosition(this.params);
            //   }
            //   break;

            // CSI P m SP }
            // Insert P s Column(s) (default = 1) (DECIC), VT420 and up.
            // case '}':
            //   if (this.postfix === ' ') {
            //     this.insertColumns(this.params);
            //   }
            //   break;

            // CSI P m SP ~
            // Delete P s Column(s) (default = 1) (DECDC), VT420 and up
            // case '~':
            //   if (this.postfix === ' ') {
            //     this.deleteColumns(this.params);
            //   }
            //   break;

          default:
            this.error('Unknown CSI code: %s.', ch);
            break;
        }

        this.prefix = '';
        this.postfix = '';
        break;

      case dcs:
        if (ch === '\x1b' || ch === '\x07') {
          if (ch === '\x1b') i++;

          switch (this.prefix) {
            // User-Defined Keys (DECUDK).
            case '':
              break;

            // Request Status String (DECRQSS).
            // test: echo -e '\eP$q"p\e\\'
            case '$q':
              var pt = this.currentParam
              , valid = false;

              switch (pt) {
                // DECSCA
                case '"q':
                  pt = '0"q';
                  break;

                // DECSCL
                case '"p':
                  pt = '61"p';
                  break;

                // DECSTBM
                case 'r':
                  pt = ''
                    + (this.scrollTop + 1)
                    + ';'
                    + (this.scrollBottom + 1)
                    + 'r';
                  break;

                // SGR
                case 'm':
                  pt = '0m';
                  break;

                default:
                  this.error('Unknown DCS Pt: %s.', pt);
                  pt = '';
                  break;
              }

              this.send('\x1bP' + +valid + '$r' + pt + '\x1b\\');
              break;

            // Set Termcap/Terminfo Data (xterm, experimental).
            case '+p':
              break;

            // Request Termcap/Terminfo String (xterm, experimental)
            // Regular xterm does not even respond to this sequence.
            // This can cause a small glitch in vim.
            // test: echo -ne '\eP+q6b64\e\\'
            case '+q':
              var pt = this.currentParam
              , valid = false;

              this.send('\x1bP' + +valid + '+r' + pt + '\x1b\\');
              break;

            default:
              this.error('Unknown DCS prefix: %s.', this.prefix);
              break;
          }

          this.currentParam = 0;
          this.prefix = '';
          this.state = normal;
        } else if (!this.currentParam) {
          if (!this.prefix && ch !== '$' && ch !== '+') {
            this.currentParam = ch;
          } else if (this.prefix.length === 2) {
            this.currentParam = ch;
          } else {
            this.prefix += ch;
          }
        } else {
          this.currentParam += ch;
        }
        break;

      case ignore:
        // For PM and APC.
        if (ch === '\x1b' || ch === '\x07') {
          if (ch === '\x1b') i++;
          this.state = normal;
        }
        break;
    }
  }

  this.updateRange(this.y);
  this.refresh(this.refreshStart, this.refreshEnd);
};

/**
 * Writes text to the terminal, followed by a break line character (\n).
 * @param {string} text The text to write to the terminal.
 */
Terminal.prototype.writeln = function(data) {
  this.write(data + '\r\n');
};

/**
 * Attaches a custom keydown handler which is run before keys are processed, giving consumers of
 * xterm.js ultimate control as to what keys should be processed by the terminal and what keys
 * should not.
 * @param {function} customKeydownHandler The custom KeyboardEvent handler to attach. This is a
 *   function that takes a KeyboardEvent, allowing consumers to stop propogation and/or prevent
 *   the default action. The function returns whether the event should be processed by xterm.js.
 */
Terminal.prototype.attachCustomKeydownHandler = function(customKeydownHandler) {
  this.customKeydownHandler = customKeydownHandler;
}

/**
 * Handle a keydown event
 * Key Resources:
 *   - https://developer.mozilla.org/en-US/docs/DOM/KeyboardEvent
 * @param {KeyboardEvent} ev The keydown event to be handled.
 */
Terminal.prototype.keyDown = function(ev) {
  if (this.customKeydownHandler && this.customKeydownHandler(ev) === false) {
    return false;
  }

  if (!this.compositionHelper.keydown.bind(this.compositionHelper)(ev)) {
    if (this.ybase !== this.ydisp) {
      this.scrollToBottom();
    }
    return false;
  }

  var self = this;
  var result = this.evaluateKeyEscapeSequence(ev);

  if (result.scrollDisp) {
    this.scrollDisp(result.scrollDisp);
    return this.cancel(ev, true);
  }

  if (isThirdLevelShift(this, ev)) {
    return true;
  }

  if (result.cancel) {
    // The event is canceled at the end already, is this necessary?
    this.cancel(ev, true);
  }

  if (!result.key) {
    return true;
  }

  this.emit('keydown', ev);
  this.emit('key', result.key, ev);
  this.showCursor();
  this.handler(result.key);

  return this.cancel(ev, true);
};

/**
 * Returns an object that determines how a KeyboardEvent should be handled. The key of the
 * returned value is the new key code to pass to the PTY.
 *
 * Reference: http://invisible-island.net/xterm/ctlseqs/ctlseqs.html
 * @param {KeyboardEvent} ev The keyboard event to be translated to key escape sequence.
 */
Terminal.prototype.evaluateKeyEscapeSequence = function(ev) {
  var result = {
    // Whether to cancel event propogation (NOTE: this may not be needed since the event is
    // canceled at the end of keyDown
    cancel: false,
    // The new key even to emit
    key: undefined,
    // The number of characters to scroll, if this is defined it will cancel the event
    scrollDisp: undefined
  };
  var modifiers = ev.shiftKey << 0 | ev.altKey << 1 | ev.ctrlKey << 2 | ev.metaKey << 3;
  switch (ev.keyCode) {
    case 8:
      // backspace
      if (ev.shiftKey) {
        result.key = '\x08'; // ^H
        break;
      }
      result.key = '\x7f'; // ^?
      break;
    case 9:
      // tab
      if (ev.shiftKey) {
        result.key = '\x1b[Z';
        break;
      }
      result.key = '\t';
      result.cancel = true;
      break;
    case 13:
      // return/enter
      result.key = '\r';
      result.cancel = true;
      break;
    case 27:
      // escape
      result.key = '\x1b';
      result.cancel = true;
      break;
    case 37:
      // left-arrow
      if (modifiers) {
        result.key = '\x1b[1;' + (modifiers + 1) + 'D';
        // HACK: Make Alt + left-arrow behave like Ctrl + left-arrow: move one word backwards
        // http://unix.stackexchange.com/a/108106
        // macOS uses different escape sequences than linux
        if (result.key == '\x1b[1;3D') {
          result.key = (this.browser.isMac) ? '\x1bb' : '\x1b[1;5D';
        }
      } else if (this.applicationCursor) {
        result.key = '\x1bOD';
      } else {
        result.key = '\x1b[D';
      }
      break;
    case 39:
      // right-arrow
      if (modifiers) {
        result.key = '\x1b[1;' + (modifiers + 1) + 'C';
        // HACK: Make Alt + right-arrow behave like Ctrl + right-arrow: move one word forward
        // http://unix.stackexchange.com/a/108106
        // macOS uses different escape sequences than linux
        if (result.key == '\x1b[1;3C') {
          result.key = (this.browser.isMac) ? '\x1bf' : '\x1b[1;5C';
        }
      } else if (this.applicationCursor) {
        result.key = '\x1bOC';
      } else {
        result.key = '\x1b[C';
      }
      break;
    case 38:
      // up-arrow
      if (modifiers) {
        result.key = '\x1b[1;' + (modifiers + 1) + 'A';
        // HACK: Make Alt + up-arrow behave like Ctrl + up-arrow
        // http://unix.stackexchange.com/a/108106
        if (result.key == '\x1b[1;3A') {
          result.key = '\x1b[1;5A';
        }
      } else if (this.applicationCursor) {
        result.key = '\x1bOA';
      } else {
        result.key = '\x1b[A';
      }
      break;
    case 40:
      // down-arrow
      if (modifiers) {
        result.key = '\x1b[1;' + (modifiers + 1) + 'B';
        // HACK: Make Alt + down-arrow behave like Ctrl + down-arrow
        // http://unix.stackexchange.com/a/108106
        if (result.key == '\x1b[1;3B') {
          result.key = '\x1b[1;5B';
        }
      } else if (this.applicationCursor) {
        result.key = '\x1bOB';
      } else {
        result.key = '\x1b[B';
      }
      break;
    case 45:
      // insert
      if (!ev.shiftKey && !ev.ctrlKey) {
        // <Ctrl> or <Shift> + <Insert> are used to
        // copy-paste on some systems.
        result.key = '\x1b[2~';
      }
      break;
    case 46:
      // delete
      if (modifiers) {
        result.key = '\x1b[3;' + (modifiers + 1) + '~';
      } else {
        result.key = '\x1b[3~';
      }
      break;
    case 36:
      // home
      if (modifiers)
        result.key = '\x1b[1;' + (modifiers + 1) + 'H';
      else if (this.applicationCursor)
        result.key = '\x1bOH';
      else
        result.key = '\x1b[H';
      break;
    case 35:
      // end
      if (modifiers)
        result.key = '\x1b[1;' + (modifiers + 1) + 'F';
      else if (this.applicationCursor)
        result.key = '\x1bOF';
      else
        result.key = '\x1b[F';
      break;
    case 33:
      // page up
      if (ev.shiftKey) {
        result.scrollDisp = -(this.rows - 1);
      } else {
        result.key = '\x1b[5~';
      }
      break;
    case 34:
      // page down
      if (ev.shiftKey) {
        result.scrollDisp = this.rows - 1;
      } else {
        result.key = '\x1b[6~';
      }
      break;
    case 112:
      // F1-F12
      if (modifiers) {
        result.key = '\x1b[1;' + (modifiers + 1) + 'P';
      } else {
        result.key = '\x1bOP';
      }
      break;
    case 113:
      if (modifiers) {
        result.key = '\x1b[1;' + (modifiers + 1) + 'Q';
      } else {
        result.key = '\x1bOQ';
      }
      break;
    case 114:
      if (modifiers) {
        result.key = '\x1b[1;' + (modifiers + 1) + 'R';
      } else {
        result.key = '\x1bOR';
      }
      break;
    case 115:
      if (modifiers) {
        result.key = '\x1b[1;' + (modifiers + 1) + 'S';
      } else {
        result.key = '\x1bOS';
      }
      break;
    case 116:
      if (modifiers) {
        result.key = '\x1b[15;' + (modifiers + 1) + '~';
      } else {
        result.key = '\x1b[15~';
      }
      break;
    case 117:
      if (modifiers) {
        result.key = '\x1b[17;' + (modifiers + 1) + '~';
      } else {
        result.key = '\x1b[17~';
      }
      break;
    case 118:
      if (modifiers) {
        result.key = '\x1b[18;' + (modifiers + 1) + '~';
      } else {
        result.key = '\x1b[18~';
      }
      break;
    case 119:
      if (modifiers) {
        result.key = '\x1b[19;' + (modifiers + 1) + '~';
      } else {
        result.key = '\x1b[19~';
      }
      break;
    case 120:
      if (modifiers) {
        result.key = '\x1b[20;' + (modifiers + 1) + '~';
      } else {
        result.key = '\x1b[20~';
      }
      break;
    case 121:
      if (modifiers) {
        result.key = '\x1b[21;' + (modifiers + 1) + '~';
      } else {
        result.key = '\x1b[21~';
      }
      break;
    case 122:
      if (modifiers) {
        result.key = '\x1b[23;' + (modifiers + 1) + '~';
      } else {
        result.key = '\x1b[23~';
      }
      break;
    case 123:
      if (modifiers) {
        result.key = '\x1b[24;' + (modifiers + 1) + '~';
      } else {
        result.key = '\x1b[24~';
      }
      break;
    default:
      // a-z and space
      if (ev.ctrlKey && !ev.shiftKey && !ev.altKey && !ev.metaKey) {
        if (ev.keyCode >= 65 && ev.keyCode <= 90) {
          result.key = String.fromCharCode(ev.keyCode - 64);
        } else if (ev.keyCode === 32) {
          // NUL
          result.key = String.fromCharCode(0);
        } else if (ev.keyCode >= 51 && ev.keyCode <= 55) {
          // escape, file sep, group sep, record sep, unit sep
          result.key = String.fromCharCode(ev.keyCode - 51 + 27);
        } else if (ev.keyCode === 56) {
          // delete
          result.key = String.fromCharCode(127);
        } else if (ev.keyCode === 219) {
          // ^[ - Control Sequence Introducer (CSI)
          result.key = String.fromCharCode(27);
        } else if (ev.keyCode === 220) {
          // ^\ - String Terminator (ST)
          result.key = String.fromCharCode(28);
        } else if (ev.keyCode === 221) {
          // ^] - Operating System Command (OSC)
          result.key = String.fromCharCode(29);
        }
      } else if (!this.browser.isMac && ev.altKey && !ev.ctrlKey && !ev.metaKey) {
        // On Mac this is a third level shift. Use <Esc> instead.
        if (ev.keyCode >= 65 && ev.keyCode <= 90) {
          result.key = '\x1b' + String.fromCharCode(ev.keyCode + 32);
        } else if (ev.keyCode === 192) {
          result.key = '\x1b`';
        } else if (ev.keyCode >= 48 && ev.keyCode <= 57) {
          result.key = '\x1b' + (ev.keyCode - 48);
        }
      }
      break;
  }
  return result;
};

/**
 * Set the G level of the terminal
 * @param g
 */
Terminal.prototype.setgLevel = function(g) {
  this.glevel = g;
  this.charset = this.charsets[g];
};

/**
 * Set the charset for the given G level of the terminal
 * @param g
 * @param charset
 */
Terminal.prototype.setgCharset = function(g, charset) {
  this.charsets[g] = charset;
  if (this.glevel === g) {
    this.charset = charset;
  }
};

/**
 * Handle a keypress event.
 * Key Resources:
 *   - https://developer.mozilla.org/en-US/docs/DOM/KeyboardEvent
 * @param {KeyboardEvent} ev The keypress event to be handled.
 */
Terminal.prototype.keyPress = function(ev) {
  var key;

  this.cancel(ev);

  if (ev.charCode) {
    key = ev.charCode;
  } else if (ev.which == null) {
    key = ev.keyCode;
  } else if (ev.which !== 0 && ev.charCode !== 0) {
    key = ev.which;
  } else {
    return false;
  }

  if (!key || (
    (ev.altKey || ev.ctrlKey || ev.metaKey) && !isThirdLevelShift(this, ev)
  )) {
    return false;
  }

  key = String.fromCharCode(key);

  this.emit('keypress', key, ev);
  this.emit('key', key, ev);
  this.showCursor();
  this.handler(key);

  return false;
};

/**
 * Send data for handling to the terminal
 * @param {string} data
 */
Terminal.prototype.send = function(data) {
  var self = this;

  if (!this.queue) {
    setTimeout(function() {
      self.handler(self.queue);
      self.queue = '';
    }, 1);
  }

  this.queue += data;
};

/**
 * Ring the bell.
 * Note: We could do sweet things with webaudio here
 */
Terminal.prototype.bell = function() {
  if (!this.visualBell) return;
  var self = this;
  this.element.style.borderColor = 'white';
  setTimeout(function() {
    self.element.style.borderColor = '';
  }, 10);
  if (this.popOnBell) this.focus();
};

/**
 * Log the current state to the console.
 */
Terminal.prototype.log = function() {
  if (!this.debug) return;
  if (!this.context.console || !this.context.console.log) return;
  var args = Array.prototype.slice.call(arguments);
  this.context.console.log.apply(this.context.console, args);
};

/**
 * Log the current state as error to the console.
 */
Terminal.prototype.error = function() {
  if (!this.debug) return;
  if (!this.context.console || !this.context.console.error) return;
  var args = Array.prototype.slice.call(arguments);
  this.context.console.error.apply(this.context.console, args);
};

/**
 * Resizes the terminal.
 *
 * @param {number} x The number of columns to resize to.
 * @param {number} y The number of rows to resize to.
 */
Terminal.prototype.resize = function(x, y) {
  var line
  , el
  , i
  , j
  , ch
  , addToY;

  if (x === this.cols && y === this.rows) {
    return;
  }

  if (x < 1) x = 1;
  if (y < 1) y = 1;

  // resize cols
  j = this.cols;
  if (j < x) {
    ch = [this.defAttr, ' ', 1]; // does xterm use the default attr?
    i = this.lines.length;
    while (i--) {
      while (this.lines.get(i).length < x) {
        this.lines.get(i).push(ch);
      }
    }
  } else { // (j > x)
    i = this.lines.length;
    while (i--) {
      while (this.lines.get(i).length > x) {
        this.lines.get(i).pop();
      }
    }
  }
  this.setupStops(j);
  this.cols = x;

  // resize rows
  j = this.rows;
  addToY = 0;
  if (j < y) {
    el = this.element;
    while (j++ < y) {
      // y is rows, not this.y
      if (this.lines.length < y + this.ybase) {
        if (this.ybase > 0 && this.lines.length <= this.ybase + this.y + addToY + 1) {
          // There is room above the buffer and there are no empty elements below the line,
          // scroll up
          this.ybase--;
          addToY++
          if (this.ydisp > 0) {
            // Viewport is at the top of the buffer, must increase downwards
            this.ydisp--;
          }
        } else {
          // Add a blank line if there is no buffer left at the top to scroll to, or if there
          // are blank lines after the cursor
          this.lines.push(this.blankLine());
        }
      }
      if (this.children.length < y) {
        this.insertRow();
      }
    }
  } else { // (j > y)
    while (j-- > y) {
      if (this.lines.length > y + this.ybase) {
        if (this.lines.length > this.ybase + this.y + 1) {
          // The line is a blank line below the cursor, remove it
          this.lines.pop();
        } else {
          // The line is the cursor, scroll down
          this.ybase++;
          this.ydisp++;
        }
      }
      if (this.children.length > y) {
        el = this.children.shift();
        if (!el) continue;
        el.parentNode.removeChild(el);
      }
    }
  }
  this.rows = y;

  // Make sure that the cursor stays on screen
  if (this.y >= y) {
    this.y = y - 1;
  }
  if (addToY) {
    this.y += addToY;
  }

  if (this.x >= x) {
    this.x = x - 1;
  }

  this.scrollTop = 0;
  this.scrollBottom = y - 1;

  this.refresh(0, this.rows - 1);

  this.normal = null;

  this.geometry = [this.cols, this.rows];
  this.emit('resize', {terminal: this, cols: x, rows: y});
};

/**
 * Updates the range of rows to refresh
 * @param {number} y The number of rows to refresh next.
 */
Terminal.prototype.updateRange = function(y) {
  if (y < this.refreshStart) this.refreshStart = y;
  if (y > this.refreshEnd) this.refreshEnd = y;
  // if (y > this.refreshEnd) {
  //   this.refreshEnd = y;
  //   if (y > this.rows - 1) {
  //     this.refreshEnd = this.rows - 1;
  //   }
  // }
};

/**
 * Set the range of refreshing to the maximum value
 */
Terminal.prototype.maxRange = function() {
  this.refreshStart = 0;
  this.refreshEnd = this.rows - 1;
};



/**
 * Setup the tab stops.
 * @param {number} i
 */
Terminal.prototype.setupStops = function(i) {
  if (i != null) {
    if (!this.tabs[i]) {
      i = this.prevStop(i);
    }
  } else {
    this.tabs = {};
    i = 0;
  }

  for (; i < this.cols; i += 8) {
    this.tabs[i] = true;
  }
};


/**
 * Move the cursor to the previous tab stop from the given position (default is current).
 * @param {number} x The position to move the cursor to the previous tab stop.
 */
Terminal.prototype.prevStop = function(x) {
  if (x == null) x = this.x;
  while (!this.tabs[--x] && x > 0);
  return x >= this.cols
    ? this.cols - 1
  : x < 0 ? 0 : x;
};


/**
 * Move the cursor one tab stop forward from the given position (default is current).
 * @param {number} x The position to move the cursor one tab stop forward.
 */
Terminal.prototype.nextStop = function(x) {
  if (x == null) x = this.x;
  while (!this.tabs[++x] && x < this.cols);
  return x >= this.cols
    ? this.cols - 1
  : x < 0 ? 0 : x;
};


/**
 * Erase in the identified line everything from "x" to the end of the line (right).
 * @param {number} x The column from which to start erasing to the end of the line.
 * @param {number} y The line in which to operate.
 */
Terminal.prototype.eraseRight = function(x, y) {
  var line = this.lines.get(this.ybase + y)
  , ch = [this.eraseAttr(), ' ', 1]; // xterm


  for (; x < this.cols; x++) {
    line[x] = ch;
  }

  this.updateRange(y);
};



/**
 * Erase in the identified line everything from "x" to the start of the line (left).
 * @param {number} x The column from which to start erasing to the start of the line.
 * @param {number} y The line in which to operate.
 */
Terminal.prototype.eraseLeft = function(x, y) {
  var line = this.lines.get(this.ybase + y)
  , ch = [this.eraseAttr(), ' ', 1]; // xterm

  x++;
  while (x--) line[x] = ch;

  this.updateRange(y);
};

/**
 * Clears the entire buffer, making the prompt line the new first line.
 */
Terminal.prototype.clear = function() {
  if (this.ybase === 0 && this.y === 0) {
    // Don't clear if it's already clear
    return;
  }
  this.lines.set(0, this.lines.get(this.ybase + this.y));
  this.lines.length = 1;
  this.ydisp = 0;
  this.ybase = 0;
  this.y = 0;
  for (var i = 1; i < this.rows; i++) {
    this.lines.push(this.blankLine());
  }
  this.refresh(0, this.rows - 1);
  this.emit('scroll', this.ydisp);
};

/**
 * Erase all content in the given line
 * @param {number} y The line to erase all of its contents.
 */
Terminal.prototype.eraseLine = function(y) {
  this.eraseRight(0, y);
};


/**
 * Return the data array of a blank line
 * @param {number} cur First bunch of data for each "blank" character.
 */
Terminal.prototype.blankLine = function(cur) {
  var attr = cur
  ? this.eraseAttr()
  : this.defAttr;

  var ch = [attr, ' ', 1]  // width defaults to 1 halfwidth character
  , line = []
  , i = 0;

  for (; i < this.cols; i++) {
    line[i] = ch;
  }

  return line;
};


/**
 * If cur return the back color xterm feature attribute. Else return defAttr.
 * @param {object} cur
 */
Terminal.prototype.ch = function(cur) {
  return cur
    ? [this.eraseAttr(), ' ', 1]
  : [this.defAttr, ' ', 1];
};


/**
 * Evaluate if the current erminal is the given argument.
 * @param {object} term The terminal to evaluate
 */
Terminal.prototype.is = function(term) {
  var name = this.termName;
  return (name + '').indexOf(term) === 0;
};


/**
 * Emit the 'data' event and populate the given data.
 * @param {string} data The data to populate in the event.
 */
Terminal.prototype.handler = function(data) {
  // Input is being sent to the terminal, the terminal should focus the prompt.
  if (this.ybase !== this.ydisp) {
    this.scrollToBottom();
  }
  this.emit('data', data);
};


/**
 * Emit the 'title' event and populate the given title.
 * @param {string} title The title to populate in the event.
 */
Terminal.prototype.handleTitle = function(title) {
  /**
   * This event is emitted when the title of the terminal is changed
   * from inside the terminal. The parameter is the new title.
   *
   * @event title
   */
  this.emit('title', title);
};


/**
 * ESC
 */

/**
 * ESC D Index (IND is 0x84).
 */
Terminal.prototype.index = function() {
  this.y++;
  if (this.y > this.scrollBottom) {
    this.y--;
    this.scroll();
  }
  this.state = normal;
};


/**
 * ESC M Reverse Index (RI is 0x8d).
 *
 * Move the cursor up one row, inserting a new blank line if necessary.
 */
Terminal.prototype.reverseIndex = function() {
  var j;
  if (this.y === this.scrollTop) {
    // possibly move the code below to term.reverseScroll();
    // test: echo -ne '\e[1;1H\e[44m\eM\e[0m'
    // blankLine(true) is xterm/linux behavior
    this.lines.shiftElements(this.y + this.ybase, this.rows - 1, 1);
    this.lines.set(this.y + this.ybase, this.blankLine(true));
    this.updateRange(this.scrollTop);
    this.updateRange(this.scrollBottom);
  } else {
    this.y--;
  }
  this.state = normal;
};


/**
 * ESC c Full Reset (RIS).
 */
Terminal.prototype.reset = function() {
  this.options.rows = this.rows;
  this.options.cols = this.cols;
  var customKeydownHandler = this.customKeydownHandler;
  Terminal.call(this, this.options);
  this.customKeydownHandler = customKeydownHandler;
  this.refresh(0, this.rows - 1);
  this.viewport.syncScrollArea();
};


/**
 * ESC H Tab Set (HTS is 0x88).
 */
Terminal.prototype.tabSet = function() {
  this.tabs[this.x] = true;
  this.state = normal;
};


/**
 * CSI
 */

/**
 * CSI Ps A
 * Cursor Up Ps Times (default = 1) (CUU).
 */
Terminal.prototype.cursorUp = function(params) {
  var param = params[0];
  if (param < 1) param = 1;
  this.y -= param;
  if (this.y < 0) this.y = 0;
};


/**
 * CSI Ps B
 * Cursor Down Ps Times (default = 1) (CUD).
 */
Terminal.prototype.cursorDown = function(params) {
  var param = params[0];
  if (param < 1) param = 1;
  this.y += param;
  if (this.y >= this.rows) {
    this.y = this.rows - 1;
  }
};


/**
 * CSI Ps C
 * Cursor Forward Ps Times (default = 1) (CUF).
 */
Terminal.prototype.cursorForward = function(params) {
  var param = params[0];
  if (param < 1) param = 1;
  this.x += param;
  if (this.x >= this.cols) {
    this.x = this.cols - 1;
  }
};


/**
 * CSI Ps D
 * Cursor Backward Ps Times (default = 1) (CUB).
 */
Terminal.prototype.cursorBackward = function(params) {
  var param = params[0];
  if (param < 1) param = 1;
  this.x -= param;
  if (this.x < 0) this.x = 0;
};


/**
 * CSI Ps ; Ps H
 * Cursor Position [row;column] (default = [1,1]) (CUP).
 */
Terminal.prototype.cursorPos = function(params) {
  var row, col;

  row = params[0] - 1;

  if (params.length >= 2) {
    col = params[1] - 1;
  } else {
    col = 0;
  }

  if (row < 0) {
    row = 0;
  } else if (row >= this.rows) {
    row = this.rows - 1;
  }

  if (col < 0) {
    col = 0;
  } else if (col >= this.cols) {
    col = this.cols - 1;
  }

  this.x = col;
  this.y = row;
};


/**
 * CSI Ps J  Erase in Display (ED).
 *     Ps = 0  -> Erase Below (default).
 *     Ps = 1  -> Erase Above.
 *     Ps = 2  -> Erase All.
 *     Ps = 3  -> Erase Saved Lines (xterm).
 * CSI ? Ps J
 *   Erase in Display (DECSED).
 *     Ps = 0  -> Selective Erase Below (default).
 *     Ps = 1  -> Selective Erase Above.
 *     Ps = 2  -> Selective Erase All.
 */
Terminal.prototype.eraseInDisplay = function(params) {
  var j;
  switch (params[0]) {
    case 0:
      this.eraseRight(this.x, this.y);
      j = this.y + 1;
      for (; j < this.rows; j++) {
        this.eraseLine(j);
      }
      break;
    case 1:
      this.eraseLeft(this.x, this.y);
      j = this.y;
      while (j--) {
        this.eraseLine(j);
      }
      break;
    case 2:
      j = this.rows;
      while (j--) this.eraseLine(j);
      break;
    case 3:
      ; // no saved lines
      break;
  }
};


/**
 * CSI Ps K  Erase in Line (EL).
 *     Ps = 0  -> Erase to Right (default).
 *     Ps = 1  -> Erase to Left.
 *     Ps = 2  -> Erase All.
 * CSI ? Ps K
 *   Erase in Line (DECSEL).
 *     Ps = 0  -> Selective Erase to Right (default).
 *     Ps = 1  -> Selective Erase to Left.
 *     Ps = 2  -> Selective Erase All.
 */
Terminal.prototype.eraseInLine = function(params) {
  switch (params[0]) {
    case 0:
      this.eraseRight(this.x, this.y);
      break;
    case 1:
      this.eraseLeft(this.x, this.y);
      break;
    case 2:
      this.eraseLine(this.y);
      break;
  }
};


/**
 * CSI Pm m  Character Attributes (SGR).
 *     Ps = 0  -> Normal (default).
 *     Ps = 1  -> Bold.
 *     Ps = 4  -> Underlined.
 *     Ps = 5  -> Blink (appears as Bold).
 *     Ps = 7  -> Inverse.
 *     Ps = 8  -> Invisible, i.e., hidden (VT300).
 *     Ps = 2 2  -> Normal (neither bold nor faint).
 *     Ps = 2 4  -> Not underlined.
 *     Ps = 2 5  -> Steady (not blinking).
 *     Ps = 2 7  -> Positive (not inverse).
 *     Ps = 2 8  -> Visible, i.e., not hidden (VT300).
 *     Ps = 3 0  -> Set foreground color to Black.
 *     Ps = 3 1  -> Set foreground color to Red.
 *     Ps = 3 2  -> Set foreground color to Green.
 *     Ps = 3 3  -> Set foreground color to Yellow.
 *     Ps = 3 4  -> Set foreground color to Blue.
 *     Ps = 3 5  -> Set foreground color to Magenta.
 *     Ps = 3 6  -> Set foreground color to Cyan.
 *     Ps = 3 7  -> Set foreground color to White.
 *     Ps = 3 9  -> Set foreground color to default (original).
 *     Ps = 4 0  -> Set background color to Black.
 *     Ps = 4 1  -> Set background color to Red.
 *     Ps = 4 2  -> Set background color to Green.
 *     Ps = 4 3  -> Set background color to Yellow.
 *     Ps = 4 4  -> Set background color to Blue.
 *     Ps = 4 5  -> Set background color to Magenta.
 *     Ps = 4 6  -> Set background color to Cyan.
 *     Ps = 4 7  -> Set background color to White.
 *     Ps = 4 9  -> Set background color to default (original).
 *
 *   If 16-color support is compiled, the following apply.  Assume
 *   that xterm's resources are set so that the ISO color codes are
 *   the first 8 of a set of 16.  Then the aixterm colors are the
 *   bright versions of the ISO colors:
 *     Ps = 9 0  -> Set foreground color to Black.
 *     Ps = 9 1  -> Set foreground color to Red.
 *     Ps = 9 2  -> Set foreground color to Green.
 *     Ps = 9 3  -> Set foreground color to Yellow.
 *     Ps = 9 4  -> Set foreground color to Blue.
 *     Ps = 9 5  -> Set foreground color to Magenta.
 *     Ps = 9 6  -> Set foreground color to Cyan.
 *     Ps = 9 7  -> Set foreground color to White.
 *     Ps = 1 0 0  -> Set background color to Black.
 *     Ps = 1 0 1  -> Set background color to Red.
 *     Ps = 1 0 2  -> Set background color to Green.
 *     Ps = 1 0 3  -> Set background color to Yellow.
 *     Ps = 1 0 4  -> Set background color to Blue.
 *     Ps = 1 0 5  -> Set background color to Magenta.
 *     Ps = 1 0 6  -> Set background color to Cyan.
 *     Ps = 1 0 7  -> Set background color to White.
 *
 *   If xterm is compiled with the 16-color support disabled, it
 *   supports the following, from rxvt:
 *     Ps = 1 0 0  -> Set foreground and background color to
 *     default.
 *
 *   If 88- or 256-color support is compiled, the following apply.
 *     Ps = 3 8  ; 5  ; Ps -> Set foreground color to the second
 *     Ps.
 *     Ps = 4 8  ; 5  ; Ps -> Set background color to the second
 *     Ps.
 */
Terminal.prototype.charAttributes = function(params) {
  // Optimize a single SGR0.
  if (params.length === 1 && params[0] === 0) {
    this.curAttr = this.defAttr;
    return;
  }

  var l = params.length
  , i = 0
  , flags = this.curAttr >> 18
  , fg = (this.curAttr >> 9) & 0x1ff
  , bg = this.curAttr & 0x1ff
  , p;

  for (; i < l; i++) {
    p = params[i];
    if (p >= 30 && p <= 37) {
      // fg color 8
      fg = p - 30;
    } else if (p >= 40 && p <= 47) {
      // bg color 8
      bg = p - 40;
    } else if (p >= 90 && p <= 97) {
      // fg color 16
      p += 8;
      fg = p - 90;
    } else if (p >= 100 && p <= 107) {
      // bg color 16
      p += 8;
      bg = p - 100;
    } else if (p === 0) {
      // default
      flags = this.defAttr >> 18;
      fg = (this.defAttr >> 9) & 0x1ff;
      bg = this.defAttr & 0x1ff;
      // flags = 0;
      // fg = 0x1ff;
      // bg = 0x1ff;
    } else if (p === 1) {
      // bold text
      flags |= 1;
    } else if (p === 4) {
      // underlined text
      flags |= 2;
    } else if (p === 5) {
      // blink
      flags |= 4;
    } else if (p === 7) {
      // inverse and positive
      // test with: echo -e '\e[31m\e[42mhello\e[7mworld\e[27mhi\e[m'
      flags |= 8;
    } else if (p === 8) {
      // invisible
      flags |= 16;
    } else if (p === 22) {
      // not bold
      flags &= ~1;
    } else if (p === 24) {
      // not underlined
      flags &= ~2;
    } else if (p === 25) {
      // not blink
      flags &= ~4;
    } else if (p === 27) {
      // not inverse
      flags &= ~8;
    } else if (p === 28) {
      // not invisible
      flags &= ~16;
    } else if (p === 39) {
      // reset fg
      fg = (this.defAttr >> 9) & 0x1ff;
    } else if (p === 49) {
      // reset bg
      bg = this.defAttr & 0x1ff;
    } else if (p === 38) {
      // fg color 256
      if (params[i + 1] === 2) {
        i += 2;
        fg = matchColor(
          params[i] & 0xff,
          params[i + 1] & 0xff,
          params[i + 2] & 0xff);
        if (fg === -1) fg = 0x1ff;
        i += 2;
      } else if (params[i + 1] === 5) {
        i += 2;
        p = params[i] & 0xff;
        fg = p;
      }
    } else if (p === 48) {
      // bg color 256
      if (params[i + 1] === 2) {
        i += 2;
        bg = matchColor(
          params[i] & 0xff,
          params[i + 1] & 0xff,
          params[i + 2] & 0xff);
        if (bg === -1) bg = 0x1ff;
        i += 2;
      } else if (params[i + 1] === 5) {
        i += 2;
        p = params[i] & 0xff;
        bg = p;
      }
    } else if (p === 100) {
      // reset fg/bg
      fg = (this.defAttr >> 9) & 0x1ff;
      bg = this.defAttr & 0x1ff;
    } else {
      this.error('Unknown SGR attribute: %d.', p);
    }
  }

  this.curAttr = (flags << 18) | (fg << 9) | bg;
};


/**
 * CSI Ps n  Device Status Report (DSR).
 *     Ps = 5  -> Status Report.  Result (``OK'') is
 *   CSI 0 n
 *     Ps = 6  -> Report Cursor Position (CPR) [row;column].
 *   Result is
 *   CSI r ; c R
 * CSI ? Ps n
 *   Device Status Report (DSR, DEC-specific).
 *     Ps = 6  -> Report Cursor Position (CPR) [row;column] as CSI
 *     ? r ; c R (assumes page is zero).
 *     Ps = 1 5  -> Report Printer status as CSI ? 1 0  n  (ready).
 *     or CSI ? 1 1  n  (not ready).
 *     Ps = 2 5  -> Report UDK status as CSI ? 2 0  n  (unlocked)
 *     or CSI ? 2 1  n  (locked).
 *     Ps = 2 6  -> Report Keyboard status as
 *   CSI ? 2 7  ;  1  ;  0  ;  0  n  (North American).
 *   The last two parameters apply to VT400 & up, and denote key-
 *   board ready and LK01 respectively.
 *     Ps = 5 3  -> Report Locator status as
 *   CSI ? 5 3  n  Locator available, if compiled-in, or
 *   CSI ? 5 0  n  No Locator, if not.
 */
Terminal.prototype.deviceStatus = function(params) {
  if (!this.prefix) {
    switch (params[0]) {
      case 5:
        // status report
        this.send('\x1b[0n');
        break;
      case 6:
        // cursor position
        this.send('\x1b['
                  + (this.y + 1)
                  + ';'
                  + (this.x + 1)
                  + 'R');
        break;
    }
  } else if (this.prefix === '?') {
    // modern xterm doesnt seem to
    // respond to any of these except ?6, 6, and 5
    switch (params[0]) {
      case 6:
        // cursor position
        this.send('\x1b[?'
                  + (this.y + 1)
                  + ';'
                  + (this.x + 1)
                  + 'R');
        break;
      case 15:
        // no printer
        // this.send('\x1b[?11n');
        break;
      case 25:
        // dont support user defined keys
        // this.send('\x1b[?21n');
        break;
      case 26:
        // north american keyboard
        // this.send('\x1b[?27;1;0;0n');
        break;
      case 53:
        // no dec locator/mouse
        // this.send('\x1b[?50n');
        break;
    }
  }
};


/**
 * Additions
 */

/**
 * CSI Ps @
 * Insert Ps (Blank) Character(s) (default = 1) (ICH).
 */
Terminal.prototype.insertChars = function(params) {
  var param, row, j, ch;

  param = params[0];
  if (param < 1) param = 1;

  row = this.y + this.ybase;
  j = this.x;
  ch = [this.eraseAttr(), ' ', 1]; // xterm

  while (param-- && j < this.cols) {
    this.lines.get(row).splice(j++, 0, ch);
    this.lines.get(row).pop();
  }
};

/**
 * CSI Ps E
 * Cursor Next Line Ps Times (default = 1) (CNL).
 * same as CSI Ps B ?
 */
Terminal.prototype.cursorNextLine = function(params) {
  var param = params[0];
  if (param < 1) param = 1;
  this.y += param;
  if (this.y >= this.rows) {
    this.y = this.rows - 1;
  }
  this.x = 0;
};


/**
 * CSI Ps F
 * Cursor Preceding Line Ps Times (default = 1) (CNL).
 * reuse CSI Ps A ?
 */
Terminal.prototype.cursorPrecedingLine = function(params) {
  var param = params[0];
  if (param < 1) param = 1;
  this.y -= param;
  if (this.y < 0) this.y = 0;
  this.x = 0;
};


/**
 * CSI Ps G
 * Cursor Character Absolute  [column] (default = [row,1]) (CHA).
 */
Terminal.prototype.cursorCharAbsolute = function(params) {
  var param = params[0];
  if (param < 1) param = 1;
  this.x = param - 1;
};


/**
 * CSI Ps L
 * Insert Ps Line(s) (default = 1) (IL).
 */
Terminal.prototype.insertLines = function(params) {
  var param, row, j;

  param = params[0];
  if (param < 1) param = 1;
  row = this.y + this.ybase;

  j = this.rows - 1 - this.scrollBottom;
  j = this.rows - 1 + this.ybase - j + 1;

  while (param--) {
    if (this.lines.length === this.lines.maxLength) {
      // Trim the start of lines to make room for the new line
      this.lines.trimStart(1);
      this.ybase--;
      this.ydisp--;
      row--;
      j--;
    }
    // test: echo -e '\e[44m\e[1L\e[0m'
    // blankLine(true) - xterm/linux behavior
    this.lines.splice(row, 0, this.blankLine(true));
    this.lines.splice(j, 1);
  }

  // this.maxRange();
  this.updateRange(this.y);
  this.updateRange(this.scrollBottom);
};


/**
 * CSI Ps M
 * Delete Ps Line(s) (default = 1) (DL).
 */
Terminal.prototype.deleteLines = function(params) {
  var param, row, j;

  param = params[0];
  if (param < 1) param = 1;
  row = this.y + this.ybase;

  j = this.rows - 1 - this.scrollBottom;
  j = this.rows - 1 + this.ybase - j;

  while (param--) {
    if (this.lines.length === this.lines.maxLength) {
      // Trim the start of lines to make room for the new line
      this.lines.trimStart(1);
      this.ybase -= 1;
      this.ydisp -= 1;
    }
    // test: echo -e '\e[44m\e[1M\e[0m'
    // blankLine(true) - xterm/linux behavior
    this.lines.splice(j + 1, 0, this.blankLine(true));
    this.lines.splice(row, 1);
  }

  // this.maxRange();
  this.updateRange(this.y);
  this.updateRange(this.scrollBottom);
};


/**
 * CSI Ps P
 * Delete Ps Character(s) (default = 1) (DCH).
 */
Terminal.prototype.deleteChars = function(params) {
  var param, row, ch;

  param = params[0];
  if (param < 1) param = 1;

  row = this.y + this.ybase;
  ch = [this.eraseAttr(), ' ', 1]; // xterm

  while (param--) {
    this.lines.get(row).splice(this.x, 1);
    this.lines.get(row).push(ch);
  }
};

/**
 * CSI Ps X
 * Erase Ps Character(s) (default = 1) (ECH).
 */
Terminal.prototype.eraseChars = function(params) {
  var param, row, j, ch;

  param = params[0];
  if (param < 1) param = 1;

  row = this.y + this.ybase;
  j = this.x;
  ch = [this.eraseAttr(), ' ', 1]; // xterm

  while (param-- && j < this.cols) {
    this.lines.get(row)[j++] = ch;
  }
};

/**
 * CSI Pm `  Character Position Absolute
 *   [column] (default = [row,1]) (HPA).
 */
Terminal.prototype.charPosAbsolute = function(params) {
  var param = params[0];
  if (param < 1) param = 1;
  this.x = param - 1;
  if (this.x >= this.cols) {
    this.x = this.cols - 1;
  }
};


/**
 * 141 61 a * HPR -
 * Horizontal Position Relative
 * reuse CSI Ps C ?
 */
Terminal.prototype.HPositionRelative = function(params) {
  var param = params[0];
  if (param < 1) param = 1;
  this.x += param;
  if (this.x >= this.cols) {
    this.x = this.cols - 1;
  }
};


/**
 * CSI Ps c  Send Device Attributes (Primary DA).
 *     Ps = 0  or omitted -> request attributes from terminal.  The
 *     response depends on the decTerminalID resource setting.
 *     -> CSI ? 1 ; 2 c  (``VT100 with Advanced Video Option'')
 *     -> CSI ? 1 ; 0 c  (``VT101 with No Options'')
 *     -> CSI ? 6 c  (``VT102'')
 *     -> CSI ? 6 0 ; 1 ; 2 ; 6 ; 8 ; 9 ; 1 5 ; c  (``VT220'')
 *   The VT100-style response parameters do not mean anything by
 *   themselves.  VT220 parameters do, telling the host what fea-
 *   tures the terminal supports:
 *     Ps = 1  -> 132-columns.
 *     Ps = 2  -> Printer.
 *     Ps = 6  -> Selective erase.
 *     Ps = 8  -> User-defined keys.
 *     Ps = 9  -> National replacement character sets.
 *     Ps = 1 5  -> Technical characters.
 *     Ps = 2 2  -> ANSI color, e.g., VT525.
 *     Ps = 2 9  -> ANSI text locator (i.e., DEC Locator mode).
 * CSI > Ps c
 *   Send Device Attributes (Secondary DA).
 *     Ps = 0  or omitted -> request the terminal's identification
 *     code.  The response depends on the decTerminalID resource set-
 *     ting.  It should apply only to VT220 and up, but xterm extends
 *     this to VT100.
 *     -> CSI  > Pp ; Pv ; Pc c
 *   where Pp denotes the terminal type
 *     Pp = 0  -> ``VT100''.
 *     Pp = 1  -> ``VT220''.
 *   and Pv is the firmware version (for xterm, this was originally
 *   the XFree86 patch number, starting with 95).  In a DEC termi-
 *   nal, Pc indicates the ROM cartridge registration number and is
 *   always zero.
 * More information:
 *   xterm/charproc.c - line 2012, for more information.
 *   vim responds with ^[[?0c or ^[[?1c after the terminal's response (?)
 */
Terminal.prototype.sendDeviceAttributes = function(params) {
  if (params[0] > 0) return;

  if (!this.prefix) {
    if (this.is('xterm')
        || this.is('rxvt-unicode')
        || this.is('screen')) {
      this.send('\x1b[?1;2c');
    } else if (this.is('linux')) {
      this.send('\x1b[?6c');
    }
  } else if (this.prefix === '>') {
    // xterm and urxvt
    // seem to spit this
    // out around ~370 times (?).
    if (this.is('xterm')) {
      this.send('\x1b[>0;276;0c');
    } else if (this.is('rxvt-unicode')) {
      this.send('\x1b[>85;95;0c');
    } else if (this.is('linux')) {
      // not supported by linux console.
      // linux console echoes parameters.
      this.send(params[0] + 'c');
    } else if (this.is('screen')) {
      this.send('\x1b[>83;40003;0c');
    }
  }
};


/**
 * CSI Pm d
 * Line Position Absolute  [row] (default = [1,column]) (VPA).
 */
Terminal.prototype.linePosAbsolute = function(params) {
  var param = params[0];
  if (param < 1) param = 1;
  this.y = param - 1;
  if (this.y >= this.rows) {
    this.y = this.rows - 1;
  }
};


/**
 * 145 65 e * VPR - Vertical Position Relative
 * reuse CSI Ps B ?
 */
Terminal.prototype.VPositionRelative = function(params) {
  var param = params[0];
  if (param < 1) param = 1;
  this.y += param;
  if (this.y >= this.rows) {
    this.y = this.rows - 1;
  }
};


/**
 * CSI Ps ; Ps f
 *   Horizontal and Vertical Position [row;column] (default =
 *   [1,1]) (HVP).
 */
Terminal.prototype.HVPosition = function(params) {
  if (params[0] < 1) params[0] = 1;
  if (params[1] < 1) params[1] = 1;

  this.y = params[0] - 1;
  if (this.y >= this.rows) {
    this.y = this.rows - 1;
  }

  this.x = params[1] - 1;
  if (this.x >= this.cols) {
    this.x = this.cols - 1;
  }
};


/**
 * CSI Pm h  Set Mode (SM).
 *     Ps = 2  -> Keyboard Action Mode (AM).
 *     Ps = 4  -> Insert Mode (IRM).
 *     Ps = 1 2  -> Send/receive (SRM).
 *     Ps = 2 0  -> Automatic Newline (LNM).
 * CSI ? Pm h
 *   DEC Private Mode Set (DECSET).
 *     Ps = 1  -> Application Cursor Keys (DECCKM).
 *     Ps = 2  -> Designate USASCII for character sets G0-G3
 *     (DECANM), and set VT100 mode.
 *     Ps = 3  -> 132 Column Mode (DECCOLM).
 *     Ps = 4  -> Smooth (Slow) Scroll (DECSCLM).
 *     Ps = 5  -> Reverse Video (DECSCNM).
 *     Ps = 6  -> Origin Mode (DECOM).
 *     Ps = 7  -> Wraparound Mode (DECAWM).
 *     Ps = 8  -> Auto-repeat Keys (DECARM).
 *     Ps = 9  -> Send Mouse X & Y on button press.  See the sec-
 *     tion Mouse Tracking.
 *     Ps = 1 0  -> Show toolbar (rxvt).
 *     Ps = 1 2  -> Start Blinking Cursor (att610).
 *     Ps = 1 8  -> Print form feed (DECPFF).
 *     Ps = 1 9  -> Set print extent to full screen (DECPEX).
 *     Ps = 2 5  -> Show Cursor (DECTCEM).
 *     Ps = 3 0  -> Show scrollbar (rxvt).
 *     Ps = 3 5  -> Enable font-shifting functions (rxvt).
 *     Ps = 3 8  -> Enter Tektronix Mode (DECTEK).
 *     Ps = 4 0  -> Allow 80 -> 132 Mode.
 *     Ps = 4 1  -> more(1) fix (see curses resource).
 *     Ps = 4 2  -> Enable Nation Replacement Character sets (DECN-
 *     RCM).
 *     Ps = 4 4  -> Turn On Margin Bell.
 *     Ps = 4 5  -> Reverse-wraparound Mode.
 *     Ps = 4 6  -> Start Logging.  This is normally disabled by a
 *     compile-time option.
 *     Ps = 4 7  -> Use Alternate Screen Buffer.  (This may be dis-
 *     abled by the titeInhibit resource).
 *     Ps = 6 6  -> Application keypad (DECNKM).
 *     Ps = 6 7  -> Backarrow key sends backspace (DECBKM).
 *     Ps = 1 0 0 0  -> Send Mouse X & Y on button press and
 *     release.  See the section Mouse Tracking.
 *     Ps = 1 0 0 1  -> Use Hilite Mouse Tracking.
 *     Ps = 1 0 0 2  -> Use Cell Motion Mouse Tracking.
 *     Ps = 1 0 0 3  -> Use All Motion Mouse Tracking.
 *     Ps = 1 0 0 4  -> Send FocusIn/FocusOut events.
 *     Ps = 1 0 0 5  -> Enable Extended Mouse Mode.
 *     Ps = 1 0 1 0  -> Scroll to bottom on tty output (rxvt).
 *     Ps = 1 0 1 1  -> Scroll to bottom on key press (rxvt).
 *     Ps = 1 0 3 4  -> Interpret "meta" key, sets eighth bit.
 *     (enables the eightBitInput resource).
 *     Ps = 1 0 3 5  -> Enable special modifiers for Alt and Num-
 *     Lock keys.  (This enables the numLock resource).
 *     Ps = 1 0 3 6  -> Send ESC   when Meta modifies a key.  (This
 *     enables the metaSendsEscape resource).
 *     Ps = 1 0 3 7  -> Send DEL from the editing-keypad Delete
 *     key.
 *     Ps = 1 0 3 9  -> Send ESC  when Alt modifies a key.  (This
 *     enables the altSendsEscape resource).
 *     Ps = 1 0 4 0  -> Keep selection even if not highlighted.
 *     (This enables the keepSelection resource).
 *     Ps = 1 0 4 1  -> Use the CLIPBOARD selection.  (This enables
 *     the selectToClipboard resource).
 *     Ps = 1 0 4 2  -> Enable Urgency window manager hint when
 *     Control-G is received.  (This enables the bellIsUrgent
 *     resource).
 *     Ps = 1 0 4 3  -> Enable raising of the window when Control-G
 *     is received.  (enables the popOnBell resource).
 *     Ps = 1 0 4 7  -> Use Alternate Screen Buffer.  (This may be
 *     disabled by the titeInhibit resource).
 *     Ps = 1 0 4 8  -> Save cursor as in DECSC.  (This may be dis-
 *     abled by the titeInhibit resource).
 *     Ps = 1 0 4 9  -> Save cursor as in DECSC and use Alternate
 *     Screen Buffer, clearing it first.  (This may be disabled by
 *     the titeInhibit resource).  This combines the effects of the 1
 *     0 4 7  and 1 0 4 8  modes.  Use this with terminfo-based
 *     applications rather than the 4 7  mode.
 *     Ps = 1 0 5 0  -> Set terminfo/termcap function-key mode.
 *     Ps = 1 0 5 1  -> Set Sun function-key mode.
 *     Ps = 1 0 5 2  -> Set HP function-key mode.
 *     Ps = 1 0 5 3  -> Set SCO function-key mode.
 *     Ps = 1 0 6 0  -> Set legacy keyboard emulation (X11R6).
 *     Ps = 1 0 6 1  -> Set VT220 keyboard emulation.
 *     Ps = 2 0 0 4  -> Set bracketed paste mode.
 * Modes:
 *   http: *vt100.net/docs/vt220-rm/chapter4.html
 */
Terminal.prototype.setMode = function(params) {
  if (typeof params === 'object') {
    var l = params.length
    , i = 0;

    for (; i < l; i++) {
      this.setMode(params[i]);
    }

    return;
  }

  if (!this.prefix) {
    switch (params) {
      case 4:
        this.insertMode = true;
        break;
      case 20:
        //this.convertEol = true;
        break;
    }
  } else if (this.prefix === '?') {
    switch (params) {
      case 1:
        this.applicationCursor = true;
        break;
      case 2:
        this.setgCharset(0, Terminal.charsets.US);
        this.setgCharset(1, Terminal.charsets.US);
        this.setgCharset(2, Terminal.charsets.US);
        this.setgCharset(3, Terminal.charsets.US);
        // set VT100 mode here
        break;
      case 3: // 132 col mode
        this.savedCols = this.cols;
        this.resize(132, this.rows);
        break;
      case 6:
        this.originMode = true;
        break;
      case 7:
        this.wraparoundMode = true;
        break;
      case 12:
        // this.cursorBlink = true;
        break;
      case 66:
        this.log('Serial port requested application keypad.');
        this.applicationKeypad = true;
        this.viewport.syncScrollArea();
        break;
      case 9: // X10 Mouse
        // no release, no motion, no wheel, no modifiers.
      case 1000: // vt200 mouse
        // no motion.
        // no modifiers, except control on the wheel.
      case 1002: // button event mouse
      case 1003: // any event mouse
        // any event - sends motion events,
        // even if there is no button held down.
        this.x10Mouse = params === 9;
        this.vt200Mouse = params === 1000;
        this.normalMouse = params > 1000;
        this.mouseEvents = true;
        this.element.style.cursor = 'default';
        this.log('Binding to mouse events.');
        break;
      case 1004: // send focusin/focusout events
        // focusin: ^[[I
        // focusout: ^[[O
        this.sendFocus = true;
        break;
      case 1005: // utf8 ext mode mouse
        this.utfMouse = true;
        // for wide terminals
        // simply encodes large values as utf8 characters
        break;
      case 1006: // sgr ext mode mouse
        this.sgrMouse = true;
        // for wide terminals
        // does not add 32 to fields
        // press: ^[[<b;x;yM
        // release: ^[[<b;x;ym
        break;
      case 1015: // urxvt ext mode mouse
        this.urxvtMouse = true;
        // for wide terminals
        // numbers for fields
        // press: ^[[b;x;yM
        // motion: ^[[b;x;yT
        break;
      case 25: // show cursor
        this.cursorHidden = false;
        break;
      case 1049: // alt screen buffer cursor
        //this.saveCursor();
        ; // FALL-THROUGH
      case 47: // alt screen buffer
      case 1047: // alt screen buffer
        if (!this.normal) {
          var normal = {
            lines: this.lines,
            ybase: this.ybase,
            ydisp: this.ydisp,
            x: this.x,
            y: this.y,
            scrollTop: this.scrollTop,
            scrollBottom: this.scrollBottom,
            tabs: this.tabs
            // XXX save charset(s) here?
            // charset: this.charset,
            // glevel: this.glevel,
            // charsets: this.charsets
          };
          this.reset();
          this.viewport.syncScrollArea();
          this.normal = normal;
          this.showCursor();
        }
        break;
    }
  }
};

/**
 * CSI Pm l  Reset Mode (RM).
 *     Ps = 2  -> Keyboard Action Mode (AM).
 *     Ps = 4  -> Replace Mode (IRM).
 *     Ps = 1 2  -> Send/receive (SRM).
 *     Ps = 2 0  -> Normal Linefeed (LNM).
 * CSI ? Pm l
 *   DEC Private Mode Reset (DECRST).
 *     Ps = 1  -> Normal Cursor Keys (DECCKM).
 *     Ps = 2  -> Designate VT52 mode (DECANM).
 *     Ps = 3  -> 80 Column Mode (DECCOLM).
 *     Ps = 4  -> Jump (Fast) Scroll (DECSCLM).
 *     Ps = 5  -> Normal Video (DECSCNM).
 *     Ps = 6  -> Normal Cursor Mode (DECOM).
 *     Ps = 7  -> No Wraparound Mode (DECAWM).
 *     Ps = 8  -> No Auto-repeat Keys (DECARM).
 *     Ps = 9  -> Don't send Mouse X & Y on button press.
 *     Ps = 1 0  -> Hide toolbar (rxvt).
 *     Ps = 1 2  -> Stop Blinking Cursor (att610).
 *     Ps = 1 8  -> Don't print form feed (DECPFF).
 *     Ps = 1 9  -> Limit print to scrolling region (DECPEX).
 *     Ps = 2 5  -> Hide Cursor (DECTCEM).
 *     Ps = 3 0  -> Don't show scrollbar (rxvt).
 *     Ps = 3 5  -> Disable font-shifting functions (rxvt).
 *     Ps = 4 0  -> Disallow 80 -> 132 Mode.
 *     Ps = 4 1  -> No more(1) fix (see curses resource).
 *     Ps = 4 2  -> Disable Nation Replacement Character sets (DEC-
 *     NRCM).
 *     Ps = 4 4  -> Turn Off Margin Bell.
 *     Ps = 4 5  -> No Reverse-wraparound Mode.
 *     Ps = 4 6  -> Stop Logging.  (This is normally disabled by a
 *     compile-time option).
 *     Ps = 4 7  -> Use Normal Screen Buffer.
 *     Ps = 6 6  -> Numeric keypad (DECNKM).
 *     Ps = 6 7  -> Backarrow key sends delete (DECBKM).
 *     Ps = 1 0 0 0  -> Don't send Mouse X & Y on button press and
 *     release.  See the section Mouse Tracking.
 *     Ps = 1 0 0 1  -> Don't use Hilite Mouse Tracking.
 *     Ps = 1 0 0 2  -> Don't use Cell Motion Mouse Tracking.
 *     Ps = 1 0 0 3  -> Don't use All Motion Mouse Tracking.
 *     Ps = 1 0 0 4  -> Don't send FocusIn/FocusOut events.
 *     Ps = 1 0 0 5  -> Disable Extended Mouse Mode.
 *     Ps = 1 0 1 0  -> Don't scroll to bottom on tty output
 *     (rxvt).
 *     Ps = 1 0 1 1  -> Don't scroll to bottom on key press (rxvt).
 *     Ps = 1 0 3 4  -> Don't interpret "meta" key.  (This disables
 *     the eightBitInput resource).
 *     Ps = 1 0 3 5  -> Disable special modifiers for Alt and Num-
 *     Lock keys.  (This disables the numLock resource).
 *     Ps = 1 0 3 6  -> Don't send ESC  when Meta modifies a key.
 *     (This disables the metaSendsEscape resource).
 *     Ps = 1 0 3 7  -> Send VT220 Remove from the editing-keypad
 *     Delete key.
 *     Ps = 1 0 3 9  -> Don't send ESC  when Alt modifies a key.
 *     (This disables the altSendsEscape resource).
 *     Ps = 1 0 4 0  -> Do not keep selection when not highlighted.
 *     (This disables the keepSelection resource).
 *     Ps = 1 0 4 1  -> Use the PRIMARY selection.  (This disables
 *     the selectToClipboard resource).
 *     Ps = 1 0 4 2  -> Disable Urgency window manager hint when
 *     Control-G is received.  (This disables the bellIsUrgent
 *     resource).
 *     Ps = 1 0 4 3  -> Disable raising of the window when Control-
 *     G is received.  (This disables the popOnBell resource).
 *     Ps = 1 0 4 7  -> Use Normal Screen Buffer, clearing screen
 *     first if in the Alternate Screen.  (This may be disabled by
 *     the titeInhibit resource).
 *     Ps = 1 0 4 8  -> Restore cursor as in DECRC.  (This may be
 *     disabled by the titeInhibit resource).
 *     Ps = 1 0 4 9  -> Use Normal Screen Buffer and restore cursor
 *     as in DECRC.  (This may be disabled by the titeInhibit
 *     resource).  This combines the effects of the 1 0 4 7  and 1 0
 *     4 8  modes.  Use this with terminfo-based applications rather
 *     than the 4 7  mode.
 *     Ps = 1 0 5 0  -> Reset terminfo/termcap function-key mode.
 *     Ps = 1 0 5 1  -> Reset Sun function-key mode.
 *     Ps = 1 0 5 2  -> Reset HP function-key mode.
 *     Ps = 1 0 5 3  -> Reset SCO function-key mode.
 *     Ps = 1 0 6 0  -> Reset legacy keyboard emulation (X11R6).
 *     Ps = 1 0 6 1  -> Reset keyboard emulation to Sun/PC style.
 *     Ps = 2 0 0 4  -> Reset bracketed paste mode.
 */
Terminal.prototype.resetMode = function(params) {
  if (typeof params === 'object') {
    var l = params.length
    , i = 0;

    for (; i < l; i++) {
      this.resetMode(params[i]);
    }

    return;
  }

  if (!this.prefix) {
    switch (params) {
      case 4:
        this.insertMode = false;
        break;
      case 20:
        //this.convertEol = false;
        break;
    }
  } else if (this.prefix === '?') {
    switch (params) {
      case 1:
        this.applicationCursor = false;
        break;
      case 3:
        if (this.cols === 132 && this.savedCols) {
          this.resize(this.savedCols, this.rows);
        }
        delete this.savedCols;
        break;
      case 6:
        this.originMode = false;
        break;
      case 7:
        this.wraparoundMode = false;
        break;
      case 12:
        // this.cursorBlink = false;
        break;
      case 66:
        this.log('Switching back to normal keypad.');
        this.applicationKeypad = false;
        this.viewport.syncScrollArea();
        break;
      case 9: // X10 Mouse
      case 1000: // vt200 mouse
      case 1002: // button event mouse
      case 1003: // any event mouse
        this.x10Mouse = false;
        this.vt200Mouse = false;
        this.normalMouse = false;
        this.mouseEvents = false;
        this.element.style.cursor = '';
        break;
      case 1004: // send focusin/focusout events
        this.sendFocus = false;
        break;
      case 1005: // utf8 ext mode mouse
        this.utfMouse = false;
        break;
      case 1006: // sgr ext mode mouse
        this.sgrMouse = false;
        break;
      case 1015: // urxvt ext mode mouse
        this.urxvtMouse = false;
        break;
      case 25: // hide cursor
        this.cursorHidden = true;
        break;
      case 1049: // alt screen buffer cursor
        ; // FALL-THROUGH
      case 47: // normal screen buffer
      case 1047: // normal screen buffer - clearing it first
        if (this.normal) {
          this.lines = this.normal.lines;
          this.ybase = this.normal.ybase;
          this.ydisp = this.normal.ydisp;
          this.x = this.normal.x;
          this.y = this.normal.y;
          this.scrollTop = this.normal.scrollTop;
          this.scrollBottom = this.normal.scrollBottom;
          this.tabs = this.normal.tabs;
          this.normal = null;
          // if (params === 1049) {
          //   this.x = this.savedX;
          //   this.y = this.savedY;
          // }
          this.refresh(0, this.rows - 1);
          this.viewport.syncScrollArea();
          this.showCursor();
        }
        break;
    }
  }
};


/**
 * CSI Ps ; Ps r
 *   Set Scrolling Region [top;bottom] (default = full size of win-
 *   dow) (DECSTBM).
 * CSI ? Pm r
 */
Terminal.prototype.setScrollRegion = function(params) {
  if (this.prefix) return;
  this.scrollTop = (params[0] || 1) - 1;
  this.scrollBottom = (params[1] || this.rows) - 1;
  this.x = 0;
  this.y = 0;
};


/**
 * CSI s
 *   Save cursor (ANSI.SYS).
 */
Terminal.prototype.saveCursor = function(params) {
  this.savedX = this.x;
  this.savedY = this.y;
};


/**
 * CSI u
 *   Restore cursor (ANSI.SYS).
 */
Terminal.prototype.restoreCursor = function(params) {
  this.x = this.savedX || 0;
  this.y = this.savedY || 0;
};


/**
 * Lesser Used
 */

/**
 * CSI Ps I
 *   Cursor Forward Tabulation Ps tab stops (default = 1) (CHT).
 */
Terminal.prototype.cursorForwardTab = function(params) {
  var param = params[0] || 1;
  while (param--) {
    this.x = this.nextStop();
  }
};


/**
 * CSI Ps S  Scroll up Ps lines (default = 1) (SU).
 */
Terminal.prototype.scrollUp = function(params) {
  var param = params[0] || 1;
  while (param--) {
    this.lines.splice(this.ybase + this.scrollTop, 1);
    this.lines.splice(this.ybase + this.scrollBottom, 0, this.blankLine());
  }
  // this.maxRange();
  this.updateRange(this.scrollTop);
  this.updateRange(this.scrollBottom);
};


/**
 * CSI Ps T  Scroll down Ps lines (default = 1) (SD).
 */
Terminal.prototype.scrollDown = function(params) {
  var param = params[0] || 1;
  while (param--) {
    this.lines.splice(this.ybase + this.scrollBottom, 1);
    this.lines.splice(this.ybase + this.scrollTop, 0, this.blankLine());
  }
  // this.maxRange();
  this.updateRange(this.scrollTop);
  this.updateRange(this.scrollBottom);
};


/**
 * CSI Ps ; Ps ; Ps ; Ps ; Ps T
 *   Initiate highlight mouse tracking.  Parameters are
 *   [func;startx;starty;firstrow;lastrow].  See the section Mouse
 *   Tracking.
 */
Terminal.prototype.initMouseTracking = function(params) {
  // Relevant: DECSET 1001
};


/**
 * CSI > Ps; Ps T
 *   Reset one or more features of the title modes to the default
 *   value.  Normally, "reset" disables the feature.  It is possi-
 *   ble to disable the ability to reset features by compiling a
 *   different default for the title modes into xterm.
 *     Ps = 0  -> Do not set window/icon labels using hexadecimal.
 *     Ps = 1  -> Do not query window/icon labels using hexadeci-
 *     mal.
 *     Ps = 2  -> Do not set window/icon labels using UTF-8.
 *     Ps = 3  -> Do not query window/icon labels using UTF-8.
 *   (See discussion of "Title Modes").
 */
Terminal.prototype.resetTitleModes = function(params) {
  ;
};


/**
 * CSI Ps Z  Cursor Backward Tabulation Ps tab stops (default = 1) (CBT).
 */
Terminal.prototype.cursorBackwardTab = function(params) {
  var param = params[0] || 1;
  while (param--) {
    this.x = this.prevStop();
  }
};


/**
 * CSI Ps b  Repeat the preceding graphic character Ps times (REP).
 */
Terminal.prototype.repeatPrecedingCharacter = function(params) {
  var param = params[0] || 1
  , line = this.lines.get(this.ybase + this.y)
  , ch = line[this.x - 1] || [this.defAttr, ' ', 1];

  while (param--) line[this.x++] = ch;
};


/**
 * CSI Ps g  Tab Clear (TBC).
 *     Ps = 0  -> Clear Current Column (default).
 *     Ps = 3  -> Clear All.
 * Potentially:
 *   Ps = 2  -> Clear Stops on Line.
 *   http://vt100.net/annarbor/aaa-ug/section6.html
 */
Terminal.prototype.tabClear = function(params) {
  var param = params[0];
  if (param <= 0) {
    delete this.tabs[this.x];
  } else if (param === 3) {
    this.tabs = {};
  }
};


/**
 * CSI Pm i  Media Copy (MC).
 *     Ps = 0  -> Print screen (default).
 *     Ps = 4  -> Turn off printer controller mode.
 *     Ps = 5  -> Turn on printer controller mode.
 * CSI ? Pm i
 *   Media Copy (MC, DEC-specific).
 *     Ps = 1  -> Print line containing cursor.
 *     Ps = 4  -> Turn off autoprint mode.
 *     Ps = 5  -> Turn on autoprint mode.
 *     Ps = 1  0  -> Print composed display, ignores DECPEX.
 *     Ps = 1  1  -> Print all pages.
 */
Terminal.prototype.mediaCopy = function(params) {
  ;
};


/**
 * CSI > Ps; Ps m
 *   Set or reset resource-values used by xterm to decide whether
 *   to construct escape sequences holding information about the
 *   modifiers pressed with a given key.  The first parameter iden-
 *   tifies the resource to set/reset.  The second parameter is the
 *   value to assign to the resource.  If the second parameter is
 *   omitted, the resource is reset to its initial value.
 *     Ps = 1  -> modifyCursorKeys.
 *     Ps = 2  -> modifyFunctionKeys.
 *     Ps = 4  -> modifyOtherKeys.
 *   If no parameters are given, all resources are reset to their
 *   initial values.
 */
Terminal.prototype.setResources = function(params) {
  ;
};


/**
 * CSI > Ps n
 *   Disable modifiers which may be enabled via the CSI > Ps; Ps m
 *   sequence.  This corresponds to a resource value of "-1", which
 *   cannot be set with the other sequence.  The parameter identi-
 *   fies the resource to be disabled:
 *     Ps = 1  -> modifyCursorKeys.
 *     Ps = 2  -> modifyFunctionKeys.
 *     Ps = 4  -> modifyOtherKeys.
 *   If the parameter is omitted, modifyFunctionKeys is disabled.
 *   When modifyFunctionKeys is disabled, xterm uses the modifier
 *   keys to make an extended sequence of functions rather than
 *   adding a parameter to each function key to denote the modi-
 *   fiers.
 */
Terminal.prototype.disableModifiers = function(params) {
  ;
};


/**
 * CSI > Ps p
 *   Set resource value pointerMode.  This is used by xterm to
 *   decide whether to hide the pointer cursor as the user types.
 *   Valid values for the parameter:
 *     Ps = 0  -> never hide the pointer.
 *     Ps = 1  -> hide if the mouse tracking mode is not enabled.
 *     Ps = 2  -> always hide the pointer.  If no parameter is
 *     given, xterm uses the default, which is 1 .
 */
Terminal.prototype.setPointerMode = function(params) {
  ;
};


/**
 * CSI ! p   Soft terminal reset (DECSTR).
 * http://vt100.net/docs/vt220-rm/table4-10.html
 */
Terminal.prototype.softReset = function(params) {
  this.cursorHidden = false;
  this.insertMode = false;
  this.originMode = false;
  this.wraparoundMode = false; // autowrap
  this.applicationKeypad = false; // ?
  this.viewport.syncScrollArea();
  this.applicationCursor = false;
  this.scrollTop = 0;
  this.scrollBottom = this.rows - 1;
  this.curAttr = this.defAttr;
  this.x = this.y = 0; // ?
  this.charset = null;
  this.glevel = 0; // ??
  this.charsets = [null]; // ??
};


/**
 * CSI Ps$ p
 *   Request ANSI mode (DECRQM).  For VT300 and up, reply is
 *     CSI Ps; Pm$ y
 *   where Ps is the mode number as in RM, and Pm is the mode
 *   value:
 *     0 - not recognized
 *     1 - set
 *     2 - reset
 *     3 - permanently set
 *     4 - permanently reset
 */
Terminal.prototype.requestAnsiMode = function(params) {
  ;
};


/**
 * CSI ? Ps$ p
 *   Request DEC private mode (DECRQM).  For VT300 and up, reply is
 *     CSI ? Ps; Pm$ p
 *   where Ps is the mode number as in DECSET, Pm is the mode value
 *   as in the ANSI DECRQM.
 */
Terminal.prototype.requestPrivateMode = function(params) {
  ;
};


/**
 * CSI Ps ; Ps " p
 *   Set conformance level (DECSCL).  Valid values for the first
 *   parameter:
 *     Ps = 6 1  -> VT100.
 *     Ps = 6 2  -> VT200.
 *     Ps = 6 3  -> VT300.
 *   Valid values for the second parameter:
 *     Ps = 0  -> 8-bit controls.
 *     Ps = 1  -> 7-bit controls (always set for VT100).
 *     Ps = 2  -> 8-bit controls.
 */
Terminal.prototype.setConformanceLevel = function(params) {
  ;
};


/**
 * CSI Ps q  Load LEDs (DECLL).
 *     Ps = 0  -> Clear all LEDS (default).
 *     Ps = 1  -> Light Num Lock.
 *     Ps = 2  -> Light Caps Lock.
 *     Ps = 3  -> Light Scroll Lock.
 *     Ps = 2  1  -> Extinguish Num Lock.
 *     Ps = 2  2  -> Extinguish Caps Lock.
 *     Ps = 2  3  -> Extinguish Scroll Lock.
 */
Terminal.prototype.loadLEDs = function(params) {
  ;
};


/**
 * CSI Ps SP q
 *   Set cursor style (DECSCUSR, VT520).
 *     Ps = 0  -> blinking block.
 *     Ps = 1  -> blinking block (default).
 *     Ps = 2  -> steady block.
 *     Ps = 3  -> blinking underline.
 *     Ps = 4  -> steady underline.
 */
Terminal.prototype.setCursorStyle = function(params) {
  ;
};


/**
 * CSI Ps " q
 *   Select character protection attribute (DECSCA).  Valid values
 *   for the parameter:
 *     Ps = 0  -> DECSED and DECSEL can erase (default).
 *     Ps = 1  -> DECSED and DECSEL cannot erase.
 *     Ps = 2  -> DECSED and DECSEL can erase.
 */
Terminal.prototype.setCharProtectionAttr = function(params) {
  ;
};


/**
 * CSI ? Pm r
 *   Restore DEC Private Mode Values.  The value of Ps previously
 *   saved is restored.  Ps values are the same as for DECSET.
 */
Terminal.prototype.restorePrivateValues = function(params) {
  ;
};


/**
 * CSI Pt; Pl; Pb; Pr; Ps$ r
 *   Change Attributes in Rectangular Area (DECCARA), VT400 and up.
 *     Pt; Pl; Pb; Pr denotes the rectangle.
 *     Ps denotes the SGR attributes to change: 0, 1, 4, 5, 7.
 * NOTE: xterm doesn't enable this code by default.
 */
Terminal.prototype.setAttrInRectangle = function(params) {
  var t = params[0]
  , l = params[1]
  , b = params[2]
  , r = params[3]
  , attr = params[4];

  var line
  , i;

  for (; t < b + 1; t++) {
    line = this.lines.get(this.ybase + t);
    for (i = l; i < r; i++) {
      line[i] = [attr, line[i][1]];
    }
  }

  // this.maxRange();
  this.updateRange(params[0]);
  this.updateRange(params[2]);
};


/**
 * CSI Pc; Pt; Pl; Pb; Pr$ x
 *   Fill Rectangular Area (DECFRA), VT420 and up.
 *     Pc is the character to use.
 *     Pt; Pl; Pb; Pr denotes the rectangle.
 * NOTE: xterm doesn't enable this code by default.
 */
Terminal.prototype.fillRectangle = function(params) {
  var ch = params[0]
  , t = params[1]
  , l = params[2]
  , b = params[3]
  , r = params[4];

  var line
  , i;

  for (; t < b + 1; t++) {
    line = this.lines.get(this.ybase + t);
    for (i = l; i < r; i++) {
      line[i] = [line[i][0], String.fromCharCode(ch)];
    }
  }

  // this.maxRange();
  this.updateRange(params[1]);
  this.updateRange(params[3]);
};


/**
 * CSI Ps ; Pu ' z
 *   Enable Locator Reporting (DECELR).
 *   Valid values for the first parameter:
 *     Ps = 0  -> Locator disabled (default).
 *     Ps = 1  -> Locator enabled.
 *     Ps = 2  -> Locator enabled for one report, then disabled.
 *   The second parameter specifies the coordinate unit for locator
 *   reports.
 *   Valid values for the second parameter:
 *     Pu = 0  <- or omitted -> default to character cells.
 *     Pu = 1  <- device physical pixels.
 *     Pu = 2  <- character cells.
 */
Terminal.prototype.enableLocatorReporting = function(params) {
  var val = params[0] > 0;
  //this.mouseEvents = val;
  //this.decLocator = val;
};


/**
 * CSI Pt; Pl; Pb; Pr$ z
 *   Erase Rectangular Area (DECERA), VT400 and up.
 *     Pt; Pl; Pb; Pr denotes the rectangle.
 * NOTE: xterm doesn't enable this code by default.
 */
Terminal.prototype.eraseRectangle = function(params) {
  var t = params[0]
  , l = params[1]
  , b = params[2]
  , r = params[3];

  var line
  , i
  , ch;

  ch = [this.eraseAttr(), ' ', 1]; // xterm?

  for (; t < b + 1; t++) {
    line = this.lines.get(this.ybase + t);
    for (i = l; i < r; i++) {
      line[i] = ch;
    }
  }

  // this.maxRange();
  this.updateRange(params[0]);
  this.updateRange(params[2]);
};


/**
 * CSI P m SP }
 * Insert P s Column(s) (default = 1) (DECIC), VT420 and up.
 * NOTE: xterm doesn't enable this code by default.
 */
Terminal.prototype.insertColumns = function() {
  var param = params[0]
  , l = this.ybase + this.rows
  , ch = [this.eraseAttr(), ' ', 1] // xterm?
  , i;

  while (param--) {
    for (i = this.ybase; i < l; i++) {
      this.lines.get(i).splice(this.x + 1, 0, ch);
      this.lines.get(i).pop();
    }
  }

  this.maxRange();
};


/**
 * CSI P m SP ~
 * Delete P s Column(s) (default = 1) (DECDC), VT420 and up
 * NOTE: xterm doesn't enable this code by default.
 */
Terminal.prototype.deleteColumns = function() {
  var param = params[0]
  , l = this.ybase + this.rows
  , ch = [this.eraseAttr(), ' ', 1] // xterm?
  , i;

  while (param--) {
    for (i = this.ybase; i < l; i++) {
      this.lines.get(i).splice(this.x, 1);
      this.lines.get(i).push(ch);
    }
  }

  this.maxRange();
};

/**
 * Character Sets
 */

Terminal.charsets = {};

// DEC Special Character and Line Drawing Set.
// http://vt100.net/docs/vt102-ug/table5-13.html
// A lot of curses apps use this if they see TERM=xterm.
// testing: echo -e '\e(0a\e(B'
// The xterm output sometimes seems to conflict with the
// reference above. xterm seems in line with the reference
// when running vttest however.
// The table below now uses xterm's output from vttest.
Terminal.charsets.SCLD = { // (0
  '`': '\u25c6', // '◆'
  'a': '\u2592', // '▒'
  'b': '\u0009', // '\t'
  'c': '\u000c', // '\f'
  'd': '\u000d', // '\r'
  'e': '\u000a', // '\n'
  'f': '\u00b0', // '°'
  'g': '\u00b1', // '±'
  'h': '\u2424', // '\u2424' (NL)
  'i': '\u000b', // '\v'
  'j': '\u2518', // '┘'
  'k': '\u2510', // '┐'
  'l': '\u250c', // '┌'
  'm': '\u2514', // '└'
  'n': '\u253c', // '┼'
  'o': '\u23ba', // '⎺'
  'p': '\u23bb', // '⎻'
  'q': '\u2500', // '─'
  'r': '\u23bc', // '⎼'
  's': '\u23bd', // '⎽'
  't': '\u251c', // '├'
  'u': '\u2524', // '┤'
  'v': '\u2534', // '┴'
  'w': '\u252c', // '┬'
  'x': '\u2502', // '│'
  'y': '\u2264', // '≤'
  'z': '\u2265', // '≥'
  '{': '\u03c0', // 'π'
  '|': '\u2260', // '≠'
  '}': '\u00a3', // '£'
  '~': '\u00b7'  // '·'
};

Terminal.charsets.UK = null; // (A
Terminal.charsets.US = null; // (B (USASCII)
Terminal.charsets.Dutch = null; // (4
Terminal.charsets.Finnish = null; // (C or (5
Terminal.charsets.French = null; // (R
Terminal.charsets.FrenchCanadian = null; // (Q
Terminal.charsets.German = null; // (K
Terminal.charsets.Italian = null; // (Y
Terminal.charsets.NorwegianDanish = null; // (E or (6
Terminal.charsets.Spanish = null; // (Z
Terminal.charsets.Swedish = null; // (H or (7
Terminal.charsets.Swiss = null; // (=
Terminal.charsets.ISOLatin = null; // /A

/**
 * Helpers
 */

function on(el, type, handler, capture) {
  if (!Array.isArray(el)) {
    el = [el];
  }
  el.forEach(function (element) {
    element.addEventListener(type, handler, capture || false);
  });
}

function off(el, type, handler, capture) {
  el.removeEventListener(type, handler, capture || false);
}

function cancel(ev, force) {
  if (!this.cancelEvents && !force) {
    return;
  }
  ev.preventDefault();
  ev.stopPropagation();
  return false;
}

function inherits(child, parent) {
  function f() {
    this.constructor = child;
  }
  f.prototype = parent.prototype;
  child.prototype = new f;
}

// if bold is broken, we can't
// use it in the terminal.
function isBoldBroken(document) {
  var body = document.getElementsByTagName('body')[0];
  var el = document.createElement('span');
  el.innerHTML = 'hello world';
  body.appendChild(el);
  var w1 = el.scrollWidth;
  el.style.fontWeight = 'bold';
  var w2 = el.scrollWidth;
  body.removeChild(el);
  return w1 !== w2;
}

function indexOf(obj, el) {
  var i = obj.length;
  while (i--) {
    if (obj[i] === el) return i;
  }
  return -1;
}

function isThirdLevelShift(term, ev) {
  var thirdLevelKey =
      (term.browser.isMac && ev.altKey && !ev.ctrlKey && !ev.metaKey) ||
      (term.browser.isMSWindows && ev.altKey && ev.ctrlKey && !ev.metaKey);

  if (ev.type == 'keypress') {
    return thirdLevelKey;
  }

  // Don't invoke for arrows, pageDown, home, backspace, etc. (on non-keypress events)
  return thirdLevelKey && (!ev.keyCode || ev.keyCode > 47);
}

function matchColor(r1, g1, b1) {
  var hash = (r1 << 16) | (g1 << 8) | b1;

  if (matchColor._cache[hash] != null) {
    return matchColor._cache[hash];
  }

  var ldiff = Infinity
  , li = -1
  , i = 0
  , c
  , r2
  , g2
  , b2
  , diff;

  for (; i < Terminal.vcolors.length; i++) {
    c = Terminal.vcolors[i];
    r2 = c[0];
    g2 = c[1];
    b2 = c[2];

    diff = matchColor.distance(r1, g1, b1, r2, g2, b2);

    if (diff === 0) {
      li = i;
      break;
    }

    if (diff < ldiff) {
      ldiff = diff;
      li = i;
    }
  }

  return matchColor._cache[hash] = li;
}

matchColor._cache = {};

// http://stackoverflow.com/questions/1633828
matchColor.distance = function(r1, g1, b1, r2, g2, b2) {
  return Math.pow(30 * (r1 - r2), 2)
    + Math.pow(59 * (g1 - g2), 2)
    + Math.pow(11 * (b1 - b2), 2);
};

function each(obj, iter, con) {
  if (obj.forEach) return obj.forEach(iter, con);
  for (var i = 0; i < obj.length; i++) {
    iter.call(con, obj[i], i, obj);
  }
}

function keys(obj) {
  if (Object.keys) return Object.keys(obj);
  var key, keys = [];
  for (key in obj) {
    if (Object.prototype.hasOwnProperty.call(obj, key)) {
      keys.push(key);
    }
  }
  return keys;
}

var wcwidth = (function(opts) {
  // extracted from https://www.cl.cam.ac.uk/%7Emgk25/ucs/wcwidth.c
  // combining characters
  var COMBINING = [
    [0x0300, 0x036F], [0x0483, 0x0486], [0x0488, 0x0489],
    [0x0591, 0x05BD], [0x05BF, 0x05BF], [0x05C1, 0x05C2],
    [0x05C4, 0x05C5], [0x05C7, 0x05C7], [0x0600, 0x0603],
    [0x0610, 0x0615], [0x064B, 0x065E], [0x0670, 0x0670],
    [0x06D6, 0x06E4], [0x06E7, 0x06E8], [0x06EA, 0x06ED],
    [0x070F, 0x070F], [0x0711, 0x0711], [0x0730, 0x074A],
    [0x07A6, 0x07B0], [0x07EB, 0x07F3], [0x0901, 0x0902],
    [0x093C, 0x093C], [0x0941, 0x0948], [0x094D, 0x094D],
    [0x0951, 0x0954], [0x0962, 0x0963], [0x0981, 0x0981],
    [0x09BC, 0x09BC], [0x09C1, 0x09C4], [0x09CD, 0x09CD],
    [0x09E2, 0x09E3], [0x0A01, 0x0A02], [0x0A3C, 0x0A3C],
    [0x0A41, 0x0A42], [0x0A47, 0x0A48], [0x0A4B, 0x0A4D],
    [0x0A70, 0x0A71], [0x0A81, 0x0A82], [0x0ABC, 0x0ABC],
    [0x0AC1, 0x0AC5], [0x0AC7, 0x0AC8], [0x0ACD, 0x0ACD],
    [0x0AE2, 0x0AE3], [0x0B01, 0x0B01], [0x0B3C, 0x0B3C],
    [0x0B3F, 0x0B3F], [0x0B41, 0x0B43], [0x0B4D, 0x0B4D],
    [0x0B56, 0x0B56], [0x0B82, 0x0B82], [0x0BC0, 0x0BC0],
    [0x0BCD, 0x0BCD], [0x0C3E, 0x0C40], [0x0C46, 0x0C48],
    [0x0C4A, 0x0C4D], [0x0C55, 0x0C56], [0x0CBC, 0x0CBC],
    [0x0CBF, 0x0CBF], [0x0CC6, 0x0CC6], [0x0CCC, 0x0CCD],
    [0x0CE2, 0x0CE3], [0x0D41, 0x0D43], [0x0D4D, 0x0D4D],
    [0x0DCA, 0x0DCA], [0x0DD2, 0x0DD4], [0x0DD6, 0x0DD6],
    [0x0E31, 0x0E31], [0x0E34, 0x0E3A], [0x0E47, 0x0E4E],
    [0x0EB1, 0x0EB1], [0x0EB4, 0x0EB9], [0x0EBB, 0x0EBC],
    [0x0EC8, 0x0ECD], [0x0F18, 0x0F19], [0x0F35, 0x0F35],
    [0x0F37, 0x0F37], [0x0F39, 0x0F39], [0x0F71, 0x0F7E],
    [0x0F80, 0x0F84], [0x0F86, 0x0F87], [0x0F90, 0x0F97],
    [0x0F99, 0x0FBC], [0x0FC6, 0x0FC6], [0x102D, 0x1030],
    [0x1032, 0x1032], [0x1036, 0x1037], [0x1039, 0x1039],
    [0x1058, 0x1059], [0x1160, 0x11FF], [0x135F, 0x135F],
    [0x1712, 0x1714], [0x1732, 0x1734], [0x1752, 0x1753],
    [0x1772, 0x1773], [0x17B4, 0x17B5], [0x17B7, 0x17BD],
    [0x17C6, 0x17C6], [0x17C9, 0x17D3], [0x17DD, 0x17DD],
    [0x180B, 0x180D], [0x18A9, 0x18A9], [0x1920, 0x1922],
    [0x1927, 0x1928], [0x1932, 0x1932], [0x1939, 0x193B],
    [0x1A17, 0x1A18], [0x1B00, 0x1B03], [0x1B34, 0x1B34],
    [0x1B36, 0x1B3A], [0x1B3C, 0x1B3C], [0x1B42, 0x1B42],
    [0x1B6B, 0x1B73], [0x1DC0, 0x1DCA], [0x1DFE, 0x1DFF],
    [0x200B, 0x200F], [0x202A, 0x202E], [0x2060, 0x2063],
    [0x206A, 0x206F], [0x20D0, 0x20EF], [0x302A, 0x302F],
    [0x3099, 0x309A], [0xA806, 0xA806], [0xA80B, 0xA80B],
    [0xA825, 0xA826], [0xFB1E, 0xFB1E], [0xFE00, 0xFE0F],
    [0xFE20, 0xFE23], [0xFEFF, 0xFEFF], [0xFFF9, 0xFFFB],
    [0x10A01, 0x10A03], [0x10A05, 0x10A06], [0x10A0C, 0x10A0F],
    [0x10A38, 0x10A3A], [0x10A3F, 0x10A3F], [0x1D167, 0x1D169],
    [0x1D173, 0x1D182], [0x1D185, 0x1D18B], [0x1D1AA, 0x1D1AD],
    [0x1D242, 0x1D244], [0xE0001, 0xE0001], [0xE0020, 0xE007F],
    [0xE0100, 0xE01EF]
  ];
  // binary search
  function bisearch(ucs) {
    var min = 0;
    var max = COMBINING.length - 1;
    var mid;
    if (ucs < COMBINING[0][0] || ucs > COMBINING[max][1])
      return false;
    while (max >= min) {
      mid = Math.floor((min + max) / 2);
      if (ucs > COMBINING[mid][1])
        min = mid + 1;
      else if (ucs < COMBINING[mid][0])
        max = mid - 1;
      else
        return true;
    }
    return false;
  }
  function wcwidth(ucs) {
    // test for 8-bit control characters
    if (ucs === 0)
      return opts.nul;
    if (ucs < 32 || (ucs >= 0x7f && ucs < 0xa0))
      return opts.control;
    // binary search in table of non-spacing characters
    if (bisearch(ucs))
      return 0;
    // if we arrive here, ucs is not a combining or C0/C1 control character
    return 1 +
      (
      ucs >= 0x1100 &&
      (
        ucs <= 0x115f ||                // Hangul Jamo init. consonants
        ucs == 0x2329 ||
        ucs == 0x232a ||
        (ucs >= 0x2e80 && ucs <= 0xa4cf && ucs != 0x303f) ||  // CJK..Yi
        (ucs >= 0xac00 && ucs <= 0xd7a3) ||    // Hangul Syllables
        (ucs >= 0xf900 && ucs <= 0xfaff) ||    // CJK Compat Ideographs
        (ucs >= 0xfe10 && ucs <= 0xfe19) ||    // Vertical forms
        (ucs >= 0xfe30 && ucs <= 0xfe6f) ||    // CJK Compat Forms
        (ucs >= 0xff00 && ucs <= 0xff60) ||    // Fullwidth Forms
        (ucs >= 0xffe0 && ucs <= 0xffe6) ||
        (ucs >= 0x20000 && ucs <= 0x2fffd) ||
        (ucs >= 0x30000 && ucs <= 0x3fffd)
      )
    );
  }
  return wcwidth;
})({nul: 0, control: 0});  // configurable options

/**
 * Expose
 */

Terminal.EventEmitter = EventEmitter;
Terminal.inherits = inherits;

/**
 * Adds an event listener to the terminal.
 *
 * @param {string} event The name of the event. TODO: Document all event types
 * @param {function} callback The function to call when the event is triggered.
 */
Terminal.on = on;
Terminal.off = off;
Terminal.cancel = cancel;

module.exports = Terminal;
